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1

Routes, J. M., H. Li, S. T. Bayley, S. Ryan, and D. J. Klemm. "Inhibition of IFN-stimulated gene expression and IFN induction of cytolytic resistance to natural killer cell lysis correlate with E1A-p300 binding." Journal of Immunology 156, no. 3 (February 1, 1996): 1055–61. http://dx.doi.org/10.4049/jimmunol.156.3.1055.

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Abstract Treatment of target cells with IFN induces resistance to NK cell lysis. This process is blocked by expression of E1A gene products in adenovirus (Ad)-infected and Ad-transformed cells. We compared the ability of adenovirus serotype 5 (Ad5) E1A exon 1 mutants to inhibit the induction of cytolytic resistance by IFN and block IFN-stimulated gene expression with their capacity to bind the cellular proteins p105 (retinoblastoma gene product), p107, and p300. E1A mutants that did not express conserved region 3 (CR3; residues 138-184) or contained deletions in the nonconserved regions between residues 26-35 or 86-120, bound p105, p107, and p300 and were not impaired in their capacity to block IFN-stimulated gene expression or IFN's induction of cytolytic resistance. E1A mutants with deletions in CR2 (residues 121-138) could not bind p105 or p107, but blocked IFN-stimulated gene expression and IFN's induction of cytolytic resistance. In contrast, mutants in CR1 or the N-terminal nonconserved region (residues 2, 4-25, and 48-60), which define E1A's binding site for p300, were unable to block either IFN-stimulated gene expression or IFN's induction of cytolytic resistance. We conclude that E1A's capacity to block both IFN-stimulated gene expression and IFN's induction of cytolytic resistance appears to be transduced through a pathway that involves E1A-p300 binding. The capacity of E1A to block IFN's induction of cytolytic resistance is probably secondary to E1A's more general ability to inhibit IFN-stimulated gene expression.
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2

Cui, Xue-Fan, Tadaatsu Imaizumi, Hidemi Yoshida, Ernest C. Borden, and Kei Satoh. "Retinoic acid-inducible gene-I is induced by interferon-γ and regulates the expression of interferon-γ stimulated gene 15 in MCF-7 cells." Biochemistry and Cell Biology 82, no. 3 (June 1, 2004): 401–5. http://dx.doi.org/10.1139/o04-041.

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Retinoic acid-inducible gene-І (RIG-І) is a member of the DExH box family proteins, which have diverse roles in regulation of gene expression and cellular functions. We found RIG-I mRNA and protein were expressed in MCF-7 human breast cancer cells stimulated with interferon-γ (IFN-γ). This effect of IFN-γ was observed in concentration- and time-dependent manners, and IFN-γ also induced promoter activity of RIG-I. Transfection of GFP-RIG-I cDNA into MCF-7 cells resulted in the expression of RIG-I protein in cytoplasm. Overexpression of RIG-I induced the upregulation of IFN-γ stimulated gene 15, which has the potential to amplify the immunomodulatory effects. We conclude that IFN-γ induces the expression of RIG-I, which may play a role in the immunological effects of IFN-γ.Key words: retinoic acid-inducible gene-I, interferon-γ, interferon-γ stimulated gene 15.
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3

Haque, S. J., and B. R. Williams. "Identification and characterization of an interferon (IFN)-stimulated response element-IFN-stimulated gene factor 3-independent signaling pathway for IFN-alpha." Journal of Biological Chemistry 269, no. 30 (July 1994): 19523–29. http://dx.doi.org/10.1016/s0021-9258(17)32200-7.

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4

Lew, D. J., T. Decker, I. Strehlow, and J. E. Darnell. "Overlapping elements in the guanylate-binding protein gene promoter mediate transcriptional induction by alpha and gamma interferons." Molecular and Cellular Biology 11, no. 1 (January 1991): 182–91. http://dx.doi.org/10.1128/mcb.11.1.182-191.1991.

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The gene encoding a 67-kDa cytoplasmic guanylate-binding protein (GBP) is transcriptionally induced in cells exposed to interferon of either type I (alpha interferon [IFN-alpha] or type II (IFN-gamma). The promoter of the GBP gene was cloned and found to contain an IFN-alpha-stimulated response element, which mediated the response of the GBP gene to IFN-alpha. On the basis of transfection experiments with recombinant plasmids, two different elements were delineated. Both were required to obtain the maximal response of the GBP gene to IFN-gamma: the IFN-alpha-stimulated response element and an overlapping element termed the IFN-gamma activation site. Different proteins that act on each element were investigated, and their possible involvement in IFN-gamma-induced transcriptional regulation is discussed.
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5

Lew, D. J., T. Decker, I. Strehlow, and J. E. Darnell. "Overlapping elements in the guanylate-binding protein gene promoter mediate transcriptional induction by alpha and gamma interferons." Molecular and Cellular Biology 11, no. 1 (January 1991): 182–91. http://dx.doi.org/10.1128/mcb.11.1.182.

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The gene encoding a 67-kDa cytoplasmic guanylate-binding protein (GBP) is transcriptionally induced in cells exposed to interferon of either type I (alpha interferon [IFN-alpha] or type II (IFN-gamma). The promoter of the GBP gene was cloned and found to contain an IFN-alpha-stimulated response element, which mediated the response of the GBP gene to IFN-alpha. On the basis of transfection experiments with recombinant plasmids, two different elements were delineated. Both were required to obtain the maximal response of the GBP gene to IFN-gamma: the IFN-alpha-stimulated response element and an overlapping element termed the IFN-gamma activation site. Different proteins that act on each element were investigated, and their possible involvement in IFN-gamma-induced transcriptional regulation is discussed.
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6

Komatsu, Takayuki, Kenji Takeuchi, Junko Yokoo, Yukie Tanaka, and Bin Gotoh. "Sendai Virus Blocks Alpha Interferon Signaling to Signal Transducers and Activators of Transcription." Journal of Virology 74, no. 5 (March 1, 2000): 2477–80. http://dx.doi.org/10.1128/jvi.74.5.2477-2480.2000.

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ABSTRACT We demonstrate here that Sendai virus (SeV) blocks alpha interferon (IFN-α) signaling to signal transducers and activators of transcription (STATs) in HeLa cells. IFN-α-stimulated tyrosine phosphorylation of STATs and subsequent formation of the IFN-stimulated gene factor 3 transcription complex were inhibited in SeV-infected cells, resulting in inefficient induction of IFN-stimulated gene products. None of the components of the signaling pathway—type I IFN receptor subunits Jak1, Tyk2, Stat1, Stat2, and p48—was degraded. Moreover, tyrosine phosphorylation of Jak1 in response to IFN-α was unaffected at the early phase of infection, suggesting that oligomerization of the receptor subunits proceeded normally. In contrast to Jak1, IFN-α-stimulated tyrosine phosphorylation of Tyk2 was partially inhibited. Therefore, this partial inhibition of activation of Tyk2 probably contributes to the subsequent failure in the activation of STATs.
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7

Nguyen, Nam V., James T. Tran, and David Jesse Sanchez. "HIV blocks Type I IFN signaling through disruption of STAT1 phosphorylation." Innate Immunity 24, no. 8 (October 3, 2018): 490–500. http://dx.doi.org/10.1177/1753425918803674.

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This study investigates the modulation of Type I IFN induction of an antiviral state by HIV. IFNs, including IFN-α, are key innate immune cytokines that activate the JAK/STAT pathway leading to the expression of IFN-stimulated genes. IFN-stimulated gene expression establishes the antiviral state, limiting viral infection in IFN-α-stimulated microenvironments. Our previous studies have shown that HIV proteins disrupt the induction of IFN-α by degradation of IFN-β promoter stimulator-1, an adaptor protein for the up-regulation and release of IFN-α into the local microenvironment via the retinoic acid-inducible gene 1-like receptor signaling pathway. However, IFN-α is still released from other sources such as plasmacytoid dendritic cells via TLR-dependent recognition of HIV. Here we report that the activation of the JAK/STAT pathway by IFN-α stimulation is disrupted by HIV proteins Vpu and Nef, which both reduce IFN-α induction of STAT1 phosphorylation. Thus, HIV would still be able to avoid antiviral protection induced by IFN-α in the local microenvironment. These findings show that HIV blocks multiple signaling points that would lead to the up-regulation of IFN-stimulated genes, allowing more effective replication in IFN-α-rich environments.
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8

Valente, Anthony J., Jing-feng Xie, Margaret A. Abramova, Ulrich O. Wenzel, Hanna E. Abboud, and Dana T. Graves. "A Complex Element Regulates IFN-γ-Stimulated Monocyte Chemoattractant Protein-1 Gene Transcription." Journal of Immunology 161, no. 7 (October 1, 1998): 3719–28. http://dx.doi.org/10.4049/jimmunol.161.7.3719.

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Abstract Monocyte chemoattractant protein-1 (MCP-1) is induced in chronic osseous inflammation, and is temporally and spatially correlated with monocyte recruitment. We investigated the mechanism of MCP-1 regulation in a human osteoblastic cell line in response to IFN-γ, a potent mediator of the immune inflammatory response. Nuclear run-on and stability studies demonstrated that IFN-γ stimulated MCP-1 transcription and did not enhance mRNA stabilization. Using MCP-1 promoter/reporter gene constructs, we determined that IFN-γ-enhanced MCP-1 transcription is regulated by a 29-bp element located at −227 relative to the ATG start codon. This element contains a 13-bp CT-rich sequence (GCTTCCCTTTCCT) adjacent to a IFN-γ activation site (GAS). Since deletion of the CT sequence enhanced both the magnitude and duration of IFN-γ-stimulated, GAS-mediated transcription, we have termed it the IFN response-inhibitory sequence (IRIS). The combined IRIS/GAS sequence is highly conserved in mouse, rat, and bovine MCP-1 genes. In gel-shift assays, nuclear extracts from IFN-γ-stimulated osteoblastic cells formed two specific inducible bands with labeled IRIS/GAS DNA. Both bands were supershifted by anti-STAT1 Abs, but not by Abs to STAT2, p48(ISGF-3γ), IFN-regulatory factor-1, or IFN-regulatory factor-2. Formation of one of the bands required the presence of the IRIS moiety. IRIS/GAS DNA also formed a number of specific complexes with constitutively expressed factors, none of which were affected by the above Abs. These studies establish a mechanism for IFN-γ-stimulated MCP-1 expression and identify a complex element that regulates MCP-1 gene transcription.
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9

Kanda, K., T. Decker, P. Aman, M. Wahlström, A. von Gabain, and B. Kallin. "The EBNA2-related resistance towards alpha interferon (IFN-alpha) in Burkitt's lymphoma cells effects induction of IFN-induced genes but not the activation of transcription factor ISGF-3." Molecular and Cellular Biology 12, no. 11 (November 1992): 4930–36. http://dx.doi.org/10.1128/mcb.12.11.4930-4936.1992.

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Transfection of a plasmid encoding the Epstein-Barr virus (EBV) nuclear antigen 2 (EBNA2) gene confers resistance to the antiproliferative effect of alpha interferon (IFN-alpha) in EBV-negative U968 cells (P. Aman and A. von Gabain, EMBO J. 9:147-152, 1990). We studied the expression of IFN-stimulated genes (ISGs) in two pairs of Burkitt's lymphoma cell lines, differing in the expression of the putative immortalizing gene of EBV, EBNA2. In EBNA2-expressing cells, the induction of four ISGs by IFN-alpha was strongly reduced or, in some cases, abolished. Chloramphenicol acetyltransferase reporter gene constructs containing different IFN-stimulated response elements were transfected into EBNA2-negative and EBNA2-positive cells. Induction of chloramphenicol acetyltransferase activity by IFN was impaired in EBNA2-positive cells. Also, a reporter gene construct driven by an IFN-gamma-sensitive promoter element was affected. However, as revealed by gel shift assays, EBNA2-positive and EBNA2-negative cells exhibited a nearly identical pattern of IFN-stimulated response element-binding proteins. Most important, activation of the factor ISGF-3, which previously has been shown to be required and sufficient for transcriptional activation of IFN-induced genes, was not inhibited in IFN-resistant cells expressing EBNA2. The mechanism of the EBNA2-related IFN resistance seems to be distinct both from the resistance mediated by hepatitis virus and adenovirus gene products and from the IFN resistance in Daudi cell variants. In these three cases, the transcriptional block of IFN-induced genes is due to inhibition of ISGF-3 activation and binding. Our data suggest that the EBNA2-related IFN resistance in Burkitt's lymphoma cells acts downstream of the activation of ISGF-3.
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10

Kanda, K., T. Decker, P. Aman, M. Wahlström, A. von Gabain, and B. Kallin. "The EBNA2-related resistance towards alpha interferon (IFN-alpha) in Burkitt's lymphoma cells effects induction of IFN-induced genes but not the activation of transcription factor ISGF-3." Molecular and Cellular Biology 12, no. 11 (November 1992): 4930–36. http://dx.doi.org/10.1128/mcb.12.11.4930.

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Transfection of a plasmid encoding the Epstein-Barr virus (EBV) nuclear antigen 2 (EBNA2) gene confers resistance to the antiproliferative effect of alpha interferon (IFN-alpha) in EBV-negative U968 cells (P. Aman and A. von Gabain, EMBO J. 9:147-152, 1990). We studied the expression of IFN-stimulated genes (ISGs) in two pairs of Burkitt's lymphoma cell lines, differing in the expression of the putative immortalizing gene of EBV, EBNA2. In EBNA2-expressing cells, the induction of four ISGs by IFN-alpha was strongly reduced or, in some cases, abolished. Chloramphenicol acetyltransferase reporter gene constructs containing different IFN-stimulated response elements were transfected into EBNA2-negative and EBNA2-positive cells. Induction of chloramphenicol acetyltransferase activity by IFN was impaired in EBNA2-positive cells. Also, a reporter gene construct driven by an IFN-gamma-sensitive promoter element was affected. However, as revealed by gel shift assays, EBNA2-positive and EBNA2-negative cells exhibited a nearly identical pattern of IFN-stimulated response element-binding proteins. Most important, activation of the factor ISGF-3, which previously has been shown to be required and sufficient for transcriptional activation of IFN-induced genes, was not inhibited in IFN-resistant cells expressing EBNA2. The mechanism of the EBNA2-related IFN resistance seems to be distinct both from the resistance mediated by hepatitis virus and adenovirus gene products and from the IFN resistance in Daudi cell variants. In these three cases, the transcriptional block of IFN-induced genes is due to inhibition of ISGF-3 activation and binding. Our data suggest that the EBNA2-related IFN resistance in Burkitt's lymphoma cells acts downstream of the activation of ISGF-3.
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11

Geiss, Gary K., Victoria S. Carter, Yupeng He, Bartlomiej K. Kwieciszewski, Ted Holzman, Marcus J. Korth, Catherine A. Lazaro, Nelson Fausto, Roger E. Bumgarner, and Michael G. Katze. "Gene Expression Profiling of the Cellular Transcriptional Network Regulated by Alpha/Beta Interferon and Its Partial Attenuation by the Hepatitis C Virus Nonstructural 5A Protein." Journal of Virology 77, no. 11 (June 1, 2003): 6367–75. http://dx.doi.org/10.1128/jvi.77.11.6367-6375.2003.

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ABSTRACT Alpha/beta interferons (IFN-α/β) induce potent antiviral and antiproliferative responses and are used to treat a wide range of human diseases, including chronic hepatitis C virus (HCV) infection. However, for reasons that remain poorly understood, many HCV isolates are resistant to IFN therapy. To better understand the nature of the cellular IFN response, we examined the effects of IFN treatment on global gene expression by using several types of human cells, including HeLa cells, liver cell lines, and primary fetal hepatocytes. In response to IFN, 50 of the approximately 4,600 genes examined were consistently induced in each of these cell types and another 60 were induced in a cell type-specific manner. A search for IFN-stimulated response elements (ISREs) in genomic DNA located upstream of IFN-stimulated genes revealed both previously identified and novel putative ISREs. To determine whether HCV can alter IFN-regulated gene expression, we performed microarray analyses on IFN-treated HeLa cells expressing the HCV nonstructural 5A (NS5A) protein and on IFN-treated Huh7 cells containing an HCV subgenomic replicon. NS5A partially blocked the IFN-mediated induction of 14 IFN-stimulated genes, an effect that may play a role in HCV resistance to IFN. This block may occur through repression of ISRE-mediated transcription, since NS5A also inhibited the IFN-mediated induction of a reporter gene driven from an ISRE-containing promoter. In contrast, the HCV replicon had very little effect on IFN-regulated gene expression. These differences highlight the importance of comparing results from multiple model systems when investigating complex phenomena such as the cellular response to IFN and viral mechanisms of IFN resistance.
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12

Larner, A. C., E. F. Petricoin, Y. Nakagawa, and D. S. Finbloom. "IL-4 attenuates the transcriptional activation of both IFN-alpha and IFN-gamma-induced cellular gene expression in monocytes and monocytic cell lines." Journal of Immunology 150, no. 5 (March 1, 1993): 1944–50. http://dx.doi.org/10.4049/jimmunol.150.5.1944.

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Abstract The interaction of IFN-alpha and IFN-gamma with monocytes results in several actions that significantly influence the course of an immune response. Many of these effects are proinflammatory and can contribute to the degree of tissue injury at a site of inflammation. Whereas recent investigations target IL-4 as a T cell product that can antagonize some of the responses induced by IFN, little is known regarding the mechanisms involved. We have taken advantage of two well defined systems: the transcriptional activation of the cellular genes ISG-54 by IFN-alpha and IP-10 by IFN-gamma. IL-4 treatment of both the monocytic leukemia cell line, THP-1, and normal peripheral blood monocytes resulted in inhibition of IFN-induced RNA levels for both genes. Nuclear run-on assays in THP-1 cells indicated that the effects of IL-4 were due to the inhibition of the transcriptional activation of these genes by both IFN-alpha and IFN-gamma. This inhibition was not due to alteration in the binding characteristics of IFN-alpha or IFN-gamma to the cell. In the IFN-alpha system, we were able to show that IL-4 treatment resulted in reduced formation of the transcriptional activator, IFN-stimulated gene factor 3. This reduction appears to be the result of a defect in the ability of IFN alpha to activate the IFN-stimulated gene factor 3 alpha component of IFN-stimulated gene factor 3.
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13

Ohmori, Y., and T. A. Hamilton. "IFN-gamma selectively inhibits lipopolysaccharide-inducible JE/monocyte chemoattractant protein-1 and KC/GRO/melanoma growth-stimulating activity gene expression in mouse peritoneal macrophages." Journal of Immunology 153, no. 5 (September 1, 1994): 2204–12. http://dx.doi.org/10.4049/jimmunol.153.5.2204.

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Abstract IFN-gamma and LPS have both been shown to stimulate enhanced chemoattractant cytokine gene expression in mononuclear phagocytes. In this report, IFN-gamma was found to suppress LPS-induced chemokine mRNA expression in a cell type- and gene-specific fashion. Expression of JE (monocyte chemoattractant protein-1) and KC (GRO/melanoma growth-stimulating activity) mRNA in macrophages stimulated with LPS was markedly suppressed by IFN-gamma in a dose- and time-dependent fashion. LPS-induced IP-10 mRNA was unaffected by IFN-gamma under identical experimental conditions. This effect was cell type-specific because JE and KC mRNA expression in LPS-stimulated murine endothelial cells, TNF-alpha-stimulated endothelial cells, and NIH-3T3 cells were unaffected by IFN-gamma. The IFN-gamma-mediated suppression of LPS-stimulated KC mRNA expression was independent of protein synthesis and mediated at the transcriptional level. These observations indicate that IFN-gamma may function as a negative regulatory signal for the expression of some proinflammatory cytokines in macrophages. The cell type-dependent differential behavior of individual members of the chemokine family may be an important determinant of the cellular composition and outcome of an inflammatory response.
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14

Lu, H. T., J. L. Riley, G. T. Babcock, M. Huston, G. R. Stark, J. M. Boss, and R. M. Ransohoff. "Interferon (IFN) beta acts downstream of IFN-gamma-induced class II transactivator messenger RNA accumulation to block major histocompatibility complex class II gene expression and requires the 48-kD DNA-binding protein, ISGF3-gamma." Journal of Experimental Medicine 182, no. 5 (November 1, 1995): 1517–25. http://dx.doi.org/10.1084/jem.182.5.1517.

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Interferon (IFN) gamma, a cardinal proinflammatory cytokine, induces expression of the gene products of the class II locus of the major histocompatibility complex (MHC), whereas IFN-alpha or -beta suppresses MHC class II expression. The mechanism of IFN-beta-mediated MHC class II inhibition has been unclear. Recently, a novel factor termed class II transactivator (CIITA) has been identified as essential for IFN-gamma-induced MHC class II transcription. We studied the status of IFN-gamma-induced CIITA messenger RNA (mRNA) accumulation and CIITA-driven transactivation in IFN-beta-treated cells and used cell lines that had defined defects in the type I IFN response pathway to address the roles of IFN signaling components in the inhibition of MHC class II induction. IFN-beta treatment did not suppress IFN-gamma-induced accumulation of CIITA mRNA. After cells were stably transfected with CIITA, endogenous MHC class II genes were constitutively expressed, and MHC class II promoters, delivered by transfection, were actively transcribed in CIITA-expressing cells. Expression of these promoters was significantly impaired by pretreatment with IFN-beta. These results suggest that IFN-beta acts downstream of CIITA mRNA accumulation, and acts in part by reducing the functional competence of CIITA for transactivating MHC class II promoters. IFN stimulated gene factor 3 (ISGF3) gamma was essential for IFN-beta to mediate inhibition of MHC class II induction, regardless of whether MHC class II transcription was stimulated by IFN-gamma or directly by CIITA expression. Results of these experiments suggest that inhibition of MHC class II in IFN-beta-treated cells requires expression of gene(s) directed by the ISGF3-IFN-stimulated response element pathway, and that these gene product(s) may act by blocking CIITA-driven transcription of MHC class II promoters.
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15

Damore, M. A., S. A. Omori, and R. Wall. "IFN-gamma induces the kappa intron enhancer via an IFN-stimulated response element." Journal of Immunology 156, no. 7 (April 1, 1996): 2451–57. http://dx.doi.org/10.4049/jimmunol.156.7.2451.

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Abstract IFN-gamma is a potent inducer of Ig kappa light chain gene transcription in 70Z/3 pre-B cells, but the mechanism of this induction has not been elucidated. The kappa intron enhancer contains a sequence closely resembling the IFN-stimulated response element (ISRE). We have determined that the kappa intron enhancer is IFN-gamma inducible in 70Z/3 cells and that the ISRE is required for this induction. The kappa intron ISRE specifically bound IFN response factor-1 (IRF-1) and the constitutively expressed IRF-2. This ISRE is a multifunctional motif that also binds the LPS-inducible factor kappaBF-A and is located within the kappaBS region, which confers B cell specific activity to this enhancer. However, since the expression of IRF-1 is not restricted to B cells, it must not be sufficient for the induction of kappa transcription. Furthermore, in the pre-B cell line 38B9, which is representative of an earlier stage in pre-B cell development than the 70Z/3 cell line, the kappa intron enhancer was not induced by IFN-gamma despite the activation of IRF-1. These findings suggest that IFN-gamma activation of kappa gene transcription during B cell maturation may be developmentally controlled by elements that restrict the activity of the ISRE within the context of the intron enhancer.
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16

Watanabe, Takako, Naoya Sakamoto, Mina Nakagawa, Sei Kakinuma, Yasuhiro Itsui, Yuki Nishimura-Sakurai, Mayumi Ueyama, et al. "Inhibitory Effect of a Triterpenoid Compound, with or without Alpha Interferon, on Hepatitis C Virus Infection." Antimicrobial Agents and Chemotherapy 55, no. 6 (March 28, 2011): 2537–45. http://dx.doi.org/10.1128/aac.01780-10.

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ABSTRACTA lack of patient response to alpha interferon (α-IFN) plus ribavirin (RBV) treatment is a major problem in eliminating hepatitis C virus (HCV). We screened chemical libraries for compounds that enhanced cellular responses to α-IFN and identified a triterpenoid, toosendanin (TSN). Here, we studied the effects and mechanisms of action of TSN on HCV replication and its effect on α-IFN signaling. We treated HCV genotype 1b replicon-expressing cells and HCV-J6/JFH-infected cells with TSN, with or without α-IFN, and the level of HCV replication was quantified. To study the effects of TSN on α-IFN signaling, we detected components of the interferon-stimulated gene factor 3 (ISGF3), phosphorylated signal transducer and activator of transcription 1 (STAT1), and STAT2 by Western blotting analysis; expression levels of mRNA of interferon regulatory factor 9 using real-time reverse transcription-PCR (RT-PCR); and interferon-stimulated response element reporter activity and measured the expression levels of interferon-inducible genes for 2′,5′-oligoadenylate synthetase, MxA, protein kinase R, and p56 using real-time RT-PCR. TSN alone specifically inhibited expression of the HCV replicon (50% effective concentration = 20.6 nM, 50% cytotoxic concentration > 3 μM, selectivity index > 146). Pretreatment with TSN prior to α-IFN treatment was more effective in suppressing HCV replication than treatment with either drug alone. Although TSN alone did not activate the α-IFN pathway, it significantly enhanced the α-IFN-induced increase of phosphorylated STATs, interferon-stimulated response element activation, and interferon-stimulated gene expression. TSN significantly increased baseline expression of interferon regulatory factor 9, a component of interferon-stimulated gene factor 3. Antiviral effects of treatment with α-IFN can be enhanced by pretreatment with TSN. Its mechanisms of action could potentially be important to identify novel molecular targets to treat HCV infection.
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17

Lehtonen, A., S. Matikainen, and I. Julkunen. "Interferons up-regulate STAT1, STAT2, and IRF family transcription factor gene expression in human peripheral blood mononuclear cells and macrophages." Journal of Immunology 159, no. 2 (July 15, 1997): 794–803. http://dx.doi.org/10.4049/jimmunol.159.2.794.

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Abstract IFN signaling is mediated by binding of IFNs to their receptors and subsequent activation of Janus tyrosine kinase (JAK)-STAT signaling pathway. Stimulation of cells with IFN-alpha leads to the assembly of IFN-stimulated gene factor 3 transcription factor complex formed by STAT1, STAT2, and p48 protein. IFN-gamma signaling is mediated by homodimeric STAT1 protein. Although these signaling molecules are expressed constitutively, there is also evidence of transcriptional regulation by IFNs. We have characterized the expression of STAT and IFN regulatory factor (IRF) family transcription factors in primary human blood mononuclear cells and macrophages in response to IFN-alpha and IFN-gamma stimulation. We show that IFN-alpha and IFN-gamma rapidly and efficiently enhanced STAT1, STAT2, p48, and IRF-1 gene expression. IFN-gamma induced IRF-1 gene expression more strongly than IFN-alpha. Stimulation experiments in the presence of protein synthesis inhibitor, cycloheximide, suggested that these genes were activated directly by IFNs. IRF-2 gene was apparently only weakly responsive to IFNs in these cells. When macrophages were pretreated with low doses of IFN-gamma and then stimulated with IFN-alpha, clearly enhanced formation of specific transcription factor complexes was detected. This suggests that higher intracellular levels of STAT1, STAT2, and p48 protein may result in enhanced signal transduction for cytokines utilizing these transcription factors.
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18

Holzinger, Dirk, Carl Jorns, Silke Stertz, Stéphanie Boisson-Dupuis, Robert Thimme, Manfred Weidmann, Jean-Laurent Casanova, Otto Haller, and Georg Kochs. "Induction of MxA Gene Expression by Influenza A Virus Requires Type I or Type III Interferon Signaling." Journal of Virology 81, no. 14 (May 9, 2007): 7776–85. http://dx.doi.org/10.1128/jvi.00546-06.

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ABSTRACT The human MxA gene belongs to the class of interferon (IFN)-stimulated genes (ISGs) involved in antiviral resistance against influenza viruses. Here, we studied the requirements for MxA induction by influenza A virus infection. MxA is transcriptionally upregulated by type I (alpha and beta) and type III (lambda) IFNs. Therefore, MxA is widely used in gene expression studies as a reliable marker for IFN bioactivity. It is not known, however, whether viruses can directly activate MxA expression in the absence of secreted IFN. By using an NS1-deficient influenza A virus and human cells with defects in IFN production or the STAT1 gene, we studied the induction profile of MxA by real-time reverse transcriptase PCR. The NS1-deficient virus is known to be a strong activator of the IFN system because NS1 acts as a viral IFN-antagonistic protein. Nevertheless, MxA gene expression was not inducible by this virus upon infection of IFN nonproducer cells and STAT1-null cells. Likewise, neither IFN-α nor IFN-λ had a sizeable effect on the STAT1-null cells, indicating that MxA expression requires STAT1 signaling and cannot be triggered directly by virus infection. In contrast, the expression of the IFN-stimulated gene ISG56 was induced by influenza virus in these cells, confirming that ISG56 differs from MxA in being directly inducible by viral triggers in an IFN-independent way. In summary, our study reveals that MxA is a unique marker for the detection of type I and type III IFN activity during virus infections and IFN therapy.
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19

Gautam, S., J. M. Tebo, and T. A. Hamilton. "IL-4 suppresses cytokine gene expression induced by IFN-gamma and/or IL-2 in murine peritoneal macrophages." Journal of Immunology 148, no. 6 (March 15, 1992): 1725–30. http://dx.doi.org/10.4049/jimmunol.148.6.1725.

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Abstract The effect of IL-4 on inflammatory gene expression in murine peritoneal macrophages stimulated with IFN-gamma in combination with IL-2 has been examined. These agents cooperatively induce the expression of mRNA for TNF-alpha and IP-10. Murine rIL-4 suppresses cytokine mRNA expression depending on the stimulus used and the mRNA being measured. Expression of TNF-alpha mRNA in macrophages stimulated with IFN-gamma, IL-2, or the combination is markedly suppressed by IL-4 whereas LPS-induced TNF-alpha mRNA is unaffected. In contrast, IP-10 mRNA expression is more sensitive to suppression by IL-4 when stimulated by LPS than by IFN-gamma/IL-2. IL-4-mediated suppression does not alter the time course of mRNA expression. Treatment of IFN-gamma/IL-2-stimulated macrophages with cycloheximide blocks the suppressive effect of IL-4, suggesting that de novo synthesis of an intermediate protein is part of the suppressive mechanism. The IL-4-mediated suppression of IFN-gamma/IL-2-driven TNF-alpha gene expression appears to be mediated at the level of transcription. These findings support a role for IL-4 as an antiinflammatory cytokine and suggest that macrophage inflammatory function will be dependent on the precise stimulus composition of the tissue microenvironment.
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Ohmori, Y., and T. A. Hamilton. "IL-4-induced STAT6 suppresses IFN-gamma-stimulated STAT1-dependent transcription in mouse macrophages." Journal of Immunology 159, no. 11 (December 1, 1997): 5474–82. http://dx.doi.org/10.4049/jimmunol.159.11.5474.

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Abstract IL-4 suppresses the IFN-gamma-induced expression of the IFN regulatory factor-1 (IRF-1) gene, and this suppression is attenuated by increasing the amount of IFN-gamma. The effects of IFN-gamma and IL-4 on transcription of a reporter gene under control of a 1.3-kb fragment from the IRF-1 gene promoter or the STAT binding element (SBE) from this gene in the context of a heterologous promoter are similar to their effects on the endogenous IRF-1 gene. IFN-gamma-dependent transcription of reporter gene is suppressed by IL-4, but IL-4 alone has no trans-activating function. IL-4 treatment does not inhibit the tyrosine phosphorylation or nuclear translocation of IFN-gamma-activated STAT1. Rather, IFN-gamma and IL-4 independently activate STAT1 and STAT6, respectively, and both proteins bind to the IRF-1 SBE in homodimeric form. The affinity of STAT1 for the IRF-1 SBE is higher than the affinity of STAT6, as measured by competition with unlabeled oligonucleotide. These observations suggest that IL-4 may suppress IFN-gamma-stimulated transcription of the IRF-1 gene by activation of STAT6, which can compete with STAT1 for occupancy of the IRF-1 SBE when STAT1 levels are low. Suppression may be attenuated as the quantity of STAT1 relative to that of STAT6 increases in cells treated with increasing amounts of IFN-gamma and displaces STAT6.
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You, Chaelin, and Kyuho Kang. "IFN-γ synergistically activates IL23A gene in LPS-stimulated macrophages." Journal of Immunology 204, no. 1_Supplement (May 1, 2020): 152.20. http://dx.doi.org/10.4049/jimmunol.204.supp.152.20.

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Abstract The cytokine IL-23 is expressed by activated myeloid cells and contributes to the development of Th17-mediated immunity. Dysregulation of IL-23 is associated with chronic inflammatory diseases, but the molecular mechanisms underlying the regulation of IL23A gene in human macrophages, are largely unknown. Unlike murine macrophages, TLR4 signaling alone did not strongly induce expression of IL23A gene but was synergistically activated by IFN-γ priming. To identify human macrophage-specific enhancers in the IL23 gene locus, we used an integrated epigenomic approach including ATAC-seq and ChIP-seq. We found a putative enhancer which is located about 2 kb upstream of the IL23A transcription start site and binds macrophage-lineage-determining factors, such as PU.1 and C/EBP. In this putative IL-23 enhancer, histone acetylation and chromatin accessibility are synergistically increased by LPS stimulation in IFN-γ-primed macrophages. IFN-γ induced coordinate occupancy of STAT1 and IRF1 at IL23A promoter and enhancer. The expression of eRNA and the recruitment of chromatin looping-associated factors cohesin and CDK8-mediator kinase at IL23A enhancer and promoter were increased by IFN-γ priming. The functional relevance of IL-23 enhancer will be tested by eRNA-targeted knockdown and enhancer deletion experiments. These results identify the critical enhancer region in IFN-γ-mediated synergistic activation of TLR4-inducible IL-23 production in human macrophages.
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Gupta, Sanjay, Man Jiang, and Alessandra B. Pernis. "IFN-α Activates Stat6 and Leads to the Formation of Stat2:Stat6 Complexes in B Cells." Journal of Immunology 163, no. 7 (October 1, 1999): 3834–41. http://dx.doi.org/10.4049/jimmunol.163.7.3834.

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Abstract IFN-α consists of a family of highly homologous proteins, which exert pleiotropic effects on a wide variety of cell types. The biologic activities of IFN-α are mediated by its binding to a multicomponent receptor complex resulting in the activation of the Janus kinase-STAT signaling pathway. In most cell types, activation of Stat1 and Stat2 by IFN-α leads to the formation of either STAT homo-/heterodimers or of the IFN-stimulated gene factor 3 complex composed of Stat1, Stat2, and p48, a non-STAT protein. These distinct transcriptional complexes then target two different sets of cis-elements, γ-activated sites and IFN-stimulated response elements. Here, we report that IFN-α can activate complexes containing Stat6, which, until now, has been primarily associated with signaling by two cytokines with biologic overlap, IL-4 and IL-13. Induction of Stat6 complexes by IFN-α appears to be cell type specific, given that tyrosine phosphorylation of Stat6 in response to IFN-α is predominantly detected in B cells. Activation of Stat6 by IFN-α in B cells is accompanied by the formation of novel Stat2:Stat6 complexes, including an IFN-stimulated gene factor 3-like complex containing Stat2, Stat6, and p48. B cell lines resistant to the antiproliferative effects of IFN-α display a decrease in the IFN-α-mediated activation of Stat6. Activation of Stat6 as well as of Stat2:Stat6 complexes by IFN-α in B cells may allow modulation of target genes in a cell type-specific manner.
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23

Matsumoto, M., N. Tanaka, H. Harada, T. Kimura, T. Yokochi, M. Kitagawa, C. Schindler, and T. Taniguchi. "Activation of the Transcription Factor ISGF3 by Interferon-gamma." Biological Chemistry 380, no. 6 (June 1, 1999): 699–703. http://dx.doi.org/10.1515/bc.1999.087.

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AbstractThe interferon-stimulated gene factor 3 (ISGF3) transcription factor has been extensively studied in the context of the type I interferon (IFN-α/β)-mediated antiviral response; it consists of the major DNA-binding component p48, and the signal transducers and activators of transcription (Stat)1 and Stat2. We show here that type II IFN (IFN-γ) can also invoke the activation of ISGF3 in mouse primary embryonic fibroblasts. In fact, the two Stat proteins were tyrosine phosphorylated in IFN-γ stimulated cells. Our present findings reveal an additional mechanism by which these two distinct types of cytokines, IFN-α/β and -γ, can commonly elicit antiviral activities.
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De La Cruz-Rivera, Pamela C., Mohammed Kanchwala, Hanquan Liang, Ashwani Kumar, Lin-Fa Wang, Chao Xing, and John W. Schoggins. "The IFN Response in Bats Displays Distinctive IFN-Stimulated Gene Expression Kinetics with Atypical RNASEL Induction." Journal of Immunology 200, no. 1 (November 27, 2017): 209–17. http://dx.doi.org/10.4049/jimmunol.1701214.

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25

Zocco, M. A., E. Carloni, M. Pescatori, N. Saulnier, A. Lupascu, E. C. Nista, M. Novi, M. Candelli, V. Cimica, and S. Mihm. "Characterization of gene expression profile in rat Kupffer cells stimulated with IFN-α or IFN-γ." Digestive and Liver Disease 38, no. 8 (August 2006): 563–77. http://dx.doi.org/10.1016/j.dld.2006.04.015.

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26

Codrington, Alicia L., Sukhwinder L. Singh, and Patricia L. Fitzgerald-Bocarsly. "Levels of epigenetic regulators TET2 and DNMT1 correlate with virus-stimulated pDC differentiation from IFN-α producing cells to antigen presenting cells." Journal of Immunology 208, no. 1_Supplement (May 1, 2022): 50.31. http://dx.doi.org/10.4049/jimmunol.208.supp.50.31.

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Abstract Plasmacytoid dendritic cells (pDC) are potent producers of IFN-α in response to DNA and RNA viruses and subsequently mature into antigen presenting cells. We investigated the role of DNA methyltransferase 1 (DNMT1) and Ten-eleven translocation methyl-cytosine dioxygenase 2 (TET2), which are generally known as gene silencers and activators, respectively, in pDC activation. PBMC from healthy donors were stimulated with Herpes Simplex Virus (HSV) or Influenza-A virus (IAV) for 6- and 24h. PBMC were surface-stained for pDC markers CD123, HLA-DR and CD11C and co-stimulatory markers CD80 and CD86, then intracellularly for DNMT1, TET2 and IFN-α, and acquired by flow cytometry. mRNA expression of DNMT1 in purified pDC was determined by qRT-PCR. At 6h, DNMT1 protein was expressed at equivalent levels in pDC with and without stimulation and in IFN-α+ and IFN-α-pDC, and in unstimulated controls. In contrast, TET2 proteins were elevated in IFN-α+ but not IFN-α-pDC and controls at 6h. At 24h, DNMT1 increased while TET2 was reduced in stimulated pDC, correlating with high IFN-α levels at 6h and low levels at 24h. There was no change in DNMT1 gene expression in virus-stimulated vs. unstimulated controls. CD80 and CD86 were elevated at 24h compared to 6h in stimulated pDC, confirming pDC differentiation from IFN-α producing to antigen presenting cells. At the point of pDC differentiation, TET2 levels were decreased and DNMT1 increased. These results suggest that TET2 is demethylating and causing activation of genes associated with pDC IFN-α production, while DNMT1 methylates and silences genes in this pathway. This results in an initial induction of TET2 and IFN-α production followed by upregulation of co-stimulatory markers, DNMT1 and loss of IFN-α. Supported by 1. AAI trainee fellowship Careers in Immunology Fellowship Program AAI EIN #: 52-2317193 2. R01Al106125
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27

Gimeno, Ramon, Chien-Kuo Lee, Christian Schindler, and David E. Levy. "Stat1 and Stat2 but Not Stat3 Arbitrate Contradictory Growth Signals Elicited by Alpha/Beta Interferon in T Lymphocytes." Molecular and Cellular Biology 25, no. 13 (July 1, 2005): 5456–65. http://dx.doi.org/10.1128/mcb.25.13.5456-5465.2005.

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ABSTRACT Alpha/beta interferon (IFN-α/β) triggers antiviral and antiproliferative responses in target cells through modulation of gene expression. The JAK-STAT pathway is the major mediator of these biological effects through the activation of the transcription factors STAT1 and STAT2, and gene ablation studies have demonstrated that both STAT1 and STAT2 are required for most antiviral responses induced by IFN-α/β. However, additional signaling pathways are also activated by IFN. Here, we show that these additional pathways provoke a proliferative response in activated T lymphocytes. While activation of IFN-stimulated gene factor 3 produces a dominant inhibitory signal capable of overriding the mitogenic response, absence of either STAT1 or STAT2 leads to a proliferative response to IFN. Growth stimulation by IFN-α/β is independent of other STAT proteins, particularly of STAT3, since T lymphocytes from STAT1-STAT3 double-knockout mice are growth stimulated by IFN-α/β treatment. IFN-α/β can cooperate with numerous T-cell mitogens, including interleukin-2 (IL-2), IL-4, IL-7, and IL-12, and can contribute to the rapid restoration of the thymus following glucocorticoid-mediated ablation. These results underscore the complexity of the cellular response to IFN and suggest that the ultimate outcome of IFN action results from a balance between growth-inhibitory and -stimulatory effects.
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28

Génin, Pierre, Pierre Morin, and Ahmet Civas. "Impairment of Interferon-Induced IRF-7 Gene Expression due to Inhibition of ISGF3 Formation by Trichostatin A." Journal of Virology 77, no. 12 (June 15, 2003): 7113–19. http://dx.doi.org/10.1128/jvi.77.12.7113-7119.2003.

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ABSTRACT Two members of the signal transducer and activator of transcription family, STAT1 and STAT2, form, together with interferon regulatory factor 9 (IRF-9), the ISGF3 complex that activates the expression of the interferon-stimulated genes (ISG). The ISGF3 complex also participates in the virus-induced alpha/beta interferon (IFN-α/β) gene amplification cascade by up-regulating IRF-7 gene expression. Here, we show that treatment of cells with trichostatin A (TSA), a deacetylase inhibitor, inhibits the virus-induced activation of IFN-α/β promoters and dramatically reduces the ability of different ISG promoters to respond to IFN stimulation. Impairment of IFN-α/β and ISG expression by TSA in infected cells is due to the blockage of interferon-stimulated ISGF3 complex formation, which leads to the abolition of IRF-7 gene expression. We also show that the TSA-dependent inhibition of ISGF3 is related to impaired nuclear accumulation of STAT2. Our data suggest that an acetylation/deacetylation mechanism participates in the regulation of cellular distribution and function of STAT2 in IFN-α/β signaling.
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29

Dear, Anthony E., and Robert L. Medcalf. "19 Urokinase mediated induction of an interferon (IFN) responsive gene promoter may utilise IFN α-stimulated gene response elements (ISRE)." Fibrinolysis and Proteolysis 11 (October 1997): 6. http://dx.doi.org/10.1016/s0268-9499(97)80134-8.

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30

Zurney, Jennifer, Takeshi Kobayashi, Geoffrey H. Holm, Terence S. Dermody, and Barbara Sherry. "Reovirus μ2 Protein Inhibits Interferon Signaling through a Novel Mechanism Involving Nuclear Accumulation of Interferon Regulatory Factor 9." Journal of Virology 83, no. 5 (December 24, 2008): 2178–87. http://dx.doi.org/10.1128/jvi.01787-08.

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ABSTRACT The secreted cytokine alpha/beta interferon (IFN-α/β) binds its receptor to activate the Jak-STAT signal transduction pathway, leading to formation of the heterotrimeric IFN-stimulated gene factor 3 (ISGF3) transcription complex for induction of IFN-stimulated genes (ISGs) and establishment of an antiviral state. Many viruses have evolved countermeasures to inhibit the IFN pathway, thereby subverting the innate antiviral response. Here, we demonstrate that the mildly myocarditic reovirus type 1 Lang (T1L), but not the nonmyocarditic reovirus type 3 Dearing, represses IFN induction of a subset of ISGs and that this repressor function segregates with the T1L M1 gene. Concordantly, the T1L M1 gene product, μ2, dramatically inhibits IFN-β-induced reporter gene expression. Surprisingly, T1L infection does not degrade components of the ISGF3 complex or interfere with STAT1 or STAT2 nuclear translocation as has been observed for other viruses. Instead, infection with T1L or reassortant or recombinant viruses containing the T1L M1 gene results in accumulation of interferon regulatory factor 9 (IRF9) in the nucleus. This effect has not been previously described for any virus and suggests that μ2 modulates IRF9 interactions with STATs for both ISGF3 function and nuclear export. The M1 gene is a determinant of virus strain-specific differences in the IFN response, which are linked to virus strain-specific differences in induction of murine myocarditis. We find that virus-induced myocarditis is associated with repression of IFN function, providing new insights into the pathophysiology of this disease. Together, these data provide the first report of an increase in IRF9 nuclear accumulation associated with viral subversion of the IFN response and couple virus strain-specific differences in IFN antagonism to the pathogenesis of viral myocarditis.
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31

van den Pol, Anthony N., Michael D. Robek, Prabhat K. Ghosh, Koray Ozduman, Prasanthi Bandi, Matthew D. Whim, and Guido Wollmann. "Cytomegalovirus InducesInterferon-Stimulated Gene Expression and Is Attenuated by Interferon in the DevelopingBrain." Journal of Virology 81, no. 1 (October 25, 2006): 332–48. http://dx.doi.org/10.1128/jvi.01592-06.

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ABSTRACT Cytomegalovirus (CMV) is considered the most common infectious agent causing permanent neurological dysfunction in the developing brain. We have previously shown that CMV infects developing brain cells more easily than it infects mature brain cells and that this preference is independent of the host B- and T-cell responses. In the present study, we examined the innate antiviral defenses against mouse (m) and human (h) CMVs in developing and mature brain and brain cells. mCMV infection induced interferon (IFN)-stimulated gene expression by 10- to 100-fold in both glia- and neuron-enriched cultures. Treatment of primary brain cultures with IFN-α, -β, and -γ or a synthetic RNA, poly(I:C), reduced the number of mCMV-infected cells, both in older cells and in fresh cultures from embryonic mouse brains. When a viral dose that killed almost all unprotected cells was used, IFN-protected cells had a natural appearance, and when they were tested with whole-cell patch clamp recording, they appeared physiologically normal with typical resting membrane potentials and action potentials. mCMV infection increased expression of representative IFN-stimulated genes (IFIT3, OAS, LMP2, TGTP, and USP18) in both neonatal and adult brains to similarly large degrees. The robust upregulation of gene expression in the neonatal brain was associated with a much higher degree of viral replication at this stage of development. In contrast to the case for downstream gene induction, CMV upregulated IFN-α/β expression to a greater degree in the adult brain than in the neonatal brain. Similar to the case with cultured brain cells, IFN treatment of the developing brain in vivo depressed mCMV replication. In parallel work with cultured primary human brain cells, IFN and poly(I:C) treatment reduced hCMV infection and prevented virus-mediated cell death. These results suggest that coupling IFN administration with current treatments may reduce CMV infections in the developing brain.
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32

Rabbani, M. A. G., Michael Ribaudo, Ju-Tao Guo, and Sailen Barik. "Identification of Interferon-Stimulated Gene Proteins That Inhibit Human Parainfluenza Virus Type 3." Journal of Virology 90, no. 24 (October 5, 2016): 11145–56. http://dx.doi.org/10.1128/jvi.01551-16.

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ABSTRACTA major arm of cellular innate immunity is type I interferon (IFN), represented by IFN-α and IFN-β. Type I IFN transcriptionally induces a large number of cellular genes, collectively known as IFN-stimulated gene (ISG) proteins, which act as antivirals. The IFIT (interferon-induced proteins with tetratricopeptide repeats) family proteins constitute a major subclass of ISG proteins and are characterized by multiple tetratricopeptide repeats (TPRs). In this study, we have interrogated IFIT proteins for the ability to inhibit the growth of human parainfluenza virus type 3 (PIV3), a nonsegmented negative-strand RNA virus of theParamyxoviridaefamily and a major cause of respiratory disease in children. We found that IFIT1 significantly inhibited PIV3, whereas IFIT2, IFIT3, and IFIT5 were less effective or not at all. In further screening a set of ISG proteins we discovered that several other such proteins also inhibited PIV3, including IFITM1, IDO (indoleamine 2,3-dioxygenase), PKR (protein kinase, RNA activated), and viperin (virus inhibitory protein, endoplasmic reticulum associated, interferon inducible)/Cig5. The antiviral effect of IDO, the enzyme that catalyzes the first step of tryptophan degradation, could be counteracted by tryptophan. These results advance our knowledge of diverse ISG proteins functioning as antivirals and may provide novel approaches against PIV3.IMPORTANCEThe innate immunity of the host, typified by interferon (IFN), is a major antiviral defense. IFN inhibits virus growth by inducing a large number of IFN-stimulated gene (ISG) proteins, several of which have been shown to have specific antiviral functions. Parainfluenza virus type 3 (PIV3) is major pathogen of children, and no reliable vaccine or specific antiviral against it currently exists. In this article, we report several ISG proteins that strongly inhibit PIV3 growth, the use of which may allow a better antiviral regimen targeting PIV3.
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Yip-Schneider, MT, M. Horie, and HE Broxmeyer. "Transcriptional induction of pim-1 protein kinase gene expression by interferon gamma and posttranscriptional effects on costimulation with steel factor." Blood 85, no. 12 (June 15, 1995): 3494–502. http://dx.doi.org/10.1182/blood.v85.12.3494.bloodjournal85123494.

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Steel factor (SLF) synergizes with interferon gamma (IFN gamma) to stimulate proliferation of the human factor-dependent cell line MO7e. We examined the effects of IFN gamma and SLF treatment, alone or in combination, on the expression of a 33-kD cytoplasmic protein serine/threonine kinase designated pim-1 whose expression has been closely associated with proliferation induced by related myeloid cytokines. IFN gamma alone, but not SLF, stimulated expression of pim-1 RNA and protein in MO7e cells; compared with IFN gamma alone, costimulation with IFN gamma and SLF resulted in a twofold to threefold increase in pim-1 message and protein expression, correlating with synergistic effects on cell proliferation. Both IFN gamma and IFN gamma/SLF induced pim-1 mRNA in the absence of de novo protein synthesis. Nuclear run-on assays showed that, although IFN gamma alone increased the rate of pim-1 gene transcription, costimulation with IFN gamma and SLF did not further potentiate this effect; however, the stability of pim-1 message was significantly enhanced in the presence of both cytokines. An IFN gamma-responsive element within the 5′ flanking region of the pim-1 gene that could confer IFN gamma responsiveness on a heterologous promoter was identified. This sequence, designated PMGAS, formed a specific complex with Stat (signal transducers and activators of transcription) 1 alpha (the p91 subunit of the transcription factor ISGF3 [interferon-stimulated gene factor 3]) in IFN gamma-treated cell extracts, suggesting that the transcriptional effects of IFN gamma on pim-1 expression may be mediated by Stat 1 alpha.
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34

PRINCE, LAWRENCE S., PHILIP H. KARP, THOMAS O. MONINGER, and MICHAEL J. WELSH. "KGF alters gene expression in human airway epithelia: potential regulation of the inflammatory response." Physiological Genomics 6, no. 2 (July 17, 2001): 81–89. http://dx.doi.org/10.1152/physiolgenomics.2001.6.2.81.

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Keratinocyte growth factor (KGF) regulates several functions in adult and developing lung epithelia; it causes proliferation, stimulates secretion of fluid and electrolytes, enhances repair, and may minimize injury. To gain insight into the molecular processes influenced by KGF, we applied KGF to primary cultures of well-differentiated human airway epithelia and used microarray hybridization to assess the abundance of gene transcripts. Of 7,069 genes tested, KGF changed expression levels of 910. Earlier studies showed that KGF causes epithelial proliferation, and as expected, treatment altered expression of numerous genes involved in cell proliferation. We found that KGF stimulated transepithelial Cl−transport, but the number of cystic fibrosis (CF) transmembrane conductance regulator (CFTR) transcripts fell. Although transcripts for ClC-1 and ClC-7 Cl−channels increased, KGF failed to augment transepithelial Cl−transport in CF epithelia, suggesting that KGF-stimulated Cl−transport in differentiated airway epithelia depends on the CFTR Cl−channel. Interestingly, KGF decreased transcripts for many interferon (IFN)-induced genes. IFN causes trafficking of Stat dimers to the nucleus, where they activate transcription of IFN-induced genes. We found that KGF prevented the IFN-stimulated trafficking of Stat1 from the cytosol to the nucleus, suggesting a molecular mechanism for KGF-mediated suppression of the IFN-signaling pathway. These results suggest that in addition to stimulating proliferation and repair of damaged airway epithelia, KGF stimulates Cl−transport and may dampen the response of epithelial cells to inflammatory mediators.
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35

Froggatt, Heather M., Alfred T. Harding, Ryan R. Chaparian, and Nicholas S. Heaton. "ETV7 limits antiviral gene expression and control of influenza viruses." Science Signaling 14, no. 691 (July 13, 2021): eabe1194. http://dx.doi.org/10.1126/scisignal.abe1194.

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The type I interferon (IFN) response is an important component of the innate immune response to viral infection. Precise control of IFN responses is critical because insufficient expression of IFN-stimulated genes (ISGs) can lead to a failure to restrict viral spread, whereas excessive ISG activation can result in IFN-related pathologies. Although both positive and negative regulatory factors control the magnitude and duration of IFN signaling, it is also appreciated that several ISGs regulate aspects of the IFN response themselves. In this study, we performed a CRISPR activation screen to identify previously unknown regulators of the type I IFN response. We identified the strongly induced ISG encoding ETS variant transcription factor 7 (ETV7) as a negative regulator of the type I IFN response. However, ETV7 did not uniformly suppress ISG transcription. Instead, ETV7 preferentially targeted a subset of antiviral ISGs that were particularly important for IFN-mediated control of influenza viruses. Together, our data assign a function for ETV7 as an IFN response regulator and also identify ETV7 as a potential therapeutic target to increase innate antiviral responses and enhance IFN-based antiviral therapies.
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36

Petricoin, E., M. David, H. Fang, P. Grimley, A. C. Larner, and S. Vande Pol. "Human cancer cell lines express a negative transcriptional regulator of the interferon regulatory factor family of DNA binding proteins." Molecular and Cellular Biology 14, no. 2 (February 1994): 1477–86. http://dx.doi.org/10.1128/mcb.14.2.1477-1486.1994.

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Members of the interferon regulatory factor (IRF) family of DNA binding transcription factors have roles in growth regulation, antiviral responses, and transcriptional induction of interferon (IFN)-activated early response genes. The IRF family member ISGF3 gamma is the DNA binding component of IFN-stimulated gene factor 3 (ISGF3), a multicomponent complex responsible for the stimulation of IFN-alpha-responsive genes. IFN-alpha-stimulated formation of ISGF3 and subsequent gene expression can be inhibited by phorbol esters or expression of the adenovirus E1A protein. We have investigated IFN signaling in human malignant tumor cell lines of the lung, colon, ovary, cervix, and hematopoietic organs and found some of these cells to be defective for IFN-alpha-induced formation of ISGF3. In many cases, an inhibitory activity termed transcriptional knockout (TKO) correlated with nonresponsiveness. TKO purified from a human papillomavirus-negative cervical carcinoma cell line has a molecular size of 19 kDa. The purified protein interacted with the ISGF3 gamma component of ISGF3, preventing binding of ISGF3 to DNA. Purified TKO displaced ISGF3 from its DNA binding site in vitro and prevented ISGF3 gamma, IRF-1, and IRF-2 from interacting with the IFN-stimulated response element. Partially purified TKO can also directly interact with ISGF3 gamma in the absence of DNA. This protein may be involved with the development of malignancies and the inability of IFN to exert its antiproliferative and antiviral effects.
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37

Petricoin, E., M. David, H. Fang, P. Grimley, A. C. Larner, and S. Vande Pol. "Human cancer cell lines express a negative transcriptional regulator of the interferon regulatory factor family of DNA binding proteins." Molecular and Cellular Biology 14, no. 2 (February 1994): 1477–86. http://dx.doi.org/10.1128/mcb.14.2.1477.

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Members of the interferon regulatory factor (IRF) family of DNA binding transcription factors have roles in growth regulation, antiviral responses, and transcriptional induction of interferon (IFN)-activated early response genes. The IRF family member ISGF3 gamma is the DNA binding component of IFN-stimulated gene factor 3 (ISGF3), a multicomponent complex responsible for the stimulation of IFN-alpha-responsive genes. IFN-alpha-stimulated formation of ISGF3 and subsequent gene expression can be inhibited by phorbol esters or expression of the adenovirus E1A protein. We have investigated IFN signaling in human malignant tumor cell lines of the lung, colon, ovary, cervix, and hematopoietic organs and found some of these cells to be defective for IFN-alpha-induced formation of ISGF3. In many cases, an inhibitory activity termed transcriptional knockout (TKO) correlated with nonresponsiveness. TKO purified from a human papillomavirus-negative cervical carcinoma cell line has a molecular size of 19 kDa. The purified protein interacted with the ISGF3 gamma component of ISGF3, preventing binding of ISGF3 to DNA. Purified TKO displaced ISGF3 from its DNA binding site in vitro and prevented ISGF3 gamma, IRF-1, and IRF-2 from interacting with the IFN-stimulated response element. Partially purified TKO can also directly interact with ISGF3 gamma in the absence of DNA. This protein may be involved with the development of malignancies and the inability of IFN to exert its antiproliferative and antiviral effects.
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38

Hernandez, Nicholas, Isabelle Melki, Huie Jing, Tanwir Habib, Susie S. Y. Huang, Jeffrey Danielson, Tomasz Kula, et al. "Life-threatening influenza pneumonitis in a child with inherited IRF9 deficiency." Journal of Experimental Medicine 215, no. 10 (August 24, 2018): 2567–85. http://dx.doi.org/10.1084/jem.20180628.

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Life-threatening pulmonary influenza can be caused by inborn errors of type I and III IFN immunity. We report a 5-yr-old child with severe pulmonary influenza at 2 yr. She is homozygous for a loss-of-function IRF9 allele. Her cells activate gamma-activated factor (GAF) STAT1 homodimers but not IFN-stimulated gene factor 3 (ISGF3) trimers (STAT1/STAT2/IRF9) in response to IFN-α2b. The transcriptome induced by IFN-α2b in the patient’s cells is much narrower than that of control cells; however, induction of a subset of IFN-stimulated gene transcripts remains detectable. In vitro, the patient’s cells do not control three respiratory viruses, influenza A virus (IAV), parainfluenza virus (PIV), and respiratory syncytial virus (RSV). These phenotypes are rescued by wild-type IRF9, whereas silencing IRF9 expression in control cells increases viral replication. However, the child has controlled various common viruses in vivo, including respiratory viruses other than IAV. Our findings show that human IRF9- and ISGF3-dependent type I and III IFN responsive pathways are essential for controlling IAV.
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Perry, David J., Kathy J. Austin, and Thomas R. Hansen. "Cloning of Interferon-Stimulated Gene 17: The Promoter and Nuclear Proteins That Regulate Transcription." Molecular Endocrinology 13, no. 7 (July 1, 1999): 1197–206. http://dx.doi.org/10.1210/mend.13.7.0294.

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Abstract A member of the interferon-stimulated gene (ISG) family encodes a 17-kDa ubiquitin homolog called ISG17 that is induced in the bovine uterine endometrium by interferon-τ (IFN-τ) during early pregnancy. The bovine (b) ISG17 cDNA shares 30% identity with a tandem ubiquitin repeat and 70% identity with human (h) ISG15. The present experiments were designed to sequence the bISG17 gene, compare general structure with the hISG15 gene, and to identify transcription factors that were induced by IFN-τ in bovine endometrial (BEND) cells. The promoter of the bISG17 gene was similar to the hISG15 gene in placement of a tandem IFN-stimulatory response element (ISRE) at position −90, but unique in the presence of three additional ISREs at positions −123, −332, and −525. IFN-τ (25 nm) induced nuclear proteins in BEND cells that interacted with a tandem bISG17 ISRE in electrophoretic mobility shift assay (EMSA). IFN-regulatory factor-1 (IRF-1) bound to this ISRE based upon supershift EMSA using antiserum against IRF-1. IFN-τ activated STAT-1 (signal transducer and activator of transcription-1) and -2 by 0.5 h, and IRF-1 by 2 h in BEND cells. It is concluded that the bISG17 gene is similar to the hISG15 gene, retains an ISRE that interacts with IRF-1, and is possibly induced initially by the STATs and later by IRF-1 in response to IFN-τ during early pregnancy.
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40

Grzegorzewska, Alicja E. "Genetic Polymorphisms within Interferon-λ Region and Interferon-λ3 in the Human Pathophysiology: Their Contribution to Outcome, Treatment, and Prevention of Infections with Hepatotropic Viruses." Current Medicinal Chemistry 26, no. 25 (October 16, 2019): 4832–51. http://dx.doi.org/10.2174/0929867325666180719121142.

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: Genetic polymorphisms within the interferon λ (IFN-λ) chromosomal region, mainly rs12979860 of IFN-λ4 gene (IFNL4), are known as associated with spontaneous hepatitis C virus (HCV) resolution and sustained viral response to therapy with pegylated interferon- α and ribavirin. Strong linkage disequilibrium of IFNL4 rs12979860 with IFNL4 rs368234815, which is casually associated with HCV spontaneous and therapeutical eradication, at least partially explains favorable HCV outcomes attributed to major homozygosity in rs12979860. Effects of IFN-based antiviral treatment are associated with pretreatment expression of the IFN-λ1 receptor, expression of hepatic IFN-stimulated genes, production of IFN- λ4, and preactivation of the JAK-STAT signaling. Nowadays direct-acting antivirals (DAAs) became a potent tool in the treatment of hepatitis C, but IFN-λs are still under investigation as potential antivirals and might be an option in HCV infection (DAA resistance, recurrent viremia, adverse effects). : Patients with altered immunocompetence are especially prone to infections. In uremic subjects, polymorphisms within the IFN-λ chromosomal region associate with spontaneous HCV clearance, similarly like in the non-uremic population. Circulating IFN-λ3 shows a positive correlation with plasma titers of antibodies to surface antigen of hepatitis B virus (anti-HBs), which are crucial for protection against hepatitis B virus. More efficient anti-HBs production in the presence of higher IFN-λ3 levels might occur due to IFN-λ3-induced regulation of indoleamine 2,3-dioxygenase (IDO) expression. IFN-stimulated response element is a part of IDO gene promoter. It is worth further investigation whether IDO gene, circulating IDO, genetic polymorphisms within the IFN-λ region, and circulating IFN-λ3 act in concordance in immunological response to hepatotropic viruses.
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41

Stewart, M. David, Greg A. Johnson, Fuller W. Bazer, and Thomas E. Spencer. "Interferon-τ (IFNτ) Regulation of IFN-Stimulated Gene Expression in Cell Lines Lacking Specific IFN-Signaling Components*." Endocrinology 142, no. 5 (May 1, 2001): 1786–94. http://dx.doi.org/10.1210/endo.142.5.8138.

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42

Silva, Bruno Jorge de Andrade, Tamiris Lameira Bittencourt, Thyago Leal-Calvo, Mayara Abud Mendes, Rhana Berto da Silva Prata, Mayara Garcia de Mattos Barbosa, Priscila Ribeiro Andrade, et al. "Autophagy-Associated IL-15 Production Is Involved in the Pathogenesis of Leprosy Type 1 Reaction." Cells 10, no. 9 (August 27, 2021): 2215. http://dx.doi.org/10.3390/cells10092215.

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Leprosy reactional episodes are acute inflammatory events that may occur during the clinical course of the disease. Type 1 reaction (T1R) is associated with an increase in neural damage, and the understanding of the molecular pathways related to T1R onset is pivotal for the development of strategies that may effectively control the reaction. Interferon-gamma (IFN-γ) is a key cytokine associated with T1R onset and is also associated with autophagy induction. Here, we evaluated the modulation of the autophagy pathway in Mycobacterium leprae-stimulated cells in the presence or absence of IFN-γ. We observed that IFN-γ treatment promoted autophagy activation and increased the expression of genes related to the formation of phagosomes, autophagy regulation and function, or lysosomal pathways in M. leprae-stimulated cells. IFN-γ increased interleukin (IL)-15 secretion in M. leprae-stimulated THP-1 cells in a process associated with autophagy activation. We also observed higher IL15 gene expression in multibacillary (MB) patients who later developed T1R during clinical follow-up when compared to MB patients who did not develop the episode. By overlapping gene expression patterns, we observed 13 common elements shared between T1R skin lesion cells and THP-1 cells stimulated with both M. leprae and IFN-γ. Among these genes, the autophagy regulator Translocated Promoter Region, Nuclear Basket Protein (TPR) was significantly increased in T1R cells when compared with non-reactional MB cells. Overall, our results indicate that IFN-γ may induce a TPR-mediated autophagy transcriptional program in M. leprae-stimulated cells similar to that observed in skin cells during T1R by a pathway that involves IL-15 production, suggesting the involvement of this cytokine in the pathogenesis of T1R.
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43

Trotta, Rossana, David Ciarlariello, Jessica Dal Col, Jeffrey Allard, Paolo Neviani, Ramasamy Santhanam, Hsiaoyin Mao, et al. "The PP2A inhibitor SET regulates natural killer cell IFN-γ production." Journal of Experimental Medicine 204, no. 10 (September 17, 2007): 2397–405. http://dx.doi.org/10.1084/jem.20070419.

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Monokines (i.e., interleukin [IL]-12, -18, and -15) induce natural killer (NK) cells to produce interferon-γ (IFN-γ), which is a critical factor for immune surveillance of cancer and monocyte clearance of infection. We show that SET, which is a potent inhibitor of protein phosphatase type 2A (PP2A) activity, is highly expressed in human CD56bright NK cells, which produce more IFN-γ than CD56dim NK cells. SET was up-regulated upon monokine stimulation of primary human NK cells. Furthermore, ectopic overexpression of SET significantly enhanced IFN-γ gene expression in monokine-stimulated NK cells. In contrast, RNAi-mediated suppression of SET expression renders NK cells inefficient in producing high levels of IFN-γ in response to monokine costimulation. Mechanistically, suppression of PP2A activity by SET is important for IFN-γ gene expression in NK cells. In fact, treatment of primary human NK cells with the PP2A activator 1,9-dideoxy-forskolin, as well as administration of the drug to C57BL/6 mice, significantly reduced NK-dependent IFN-γ production in response to monokine treatment. Further, SET knockdown or pharmacologic activation of PP2A diminished extracellular signal-regulated kinase 1/2, p65RelA, signal transducer and activator of transduction 4 (STAT4), and STAT5 activity in monokine-stimulated NK cells, potentially contributing to the reduction in IFN-γ gene expression. Thus, SET expression is essential for suppressing PP2A phosphatase activity that would otherwise limit NK cell antitumoral and/or antiinflammatory functions by impairing NK cell production of IFN-γ.
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44

Besancon, F., G. Przewlocki, I. Baro, A. S. Hongre, D. Escande, and A. Edelman. "Interferon-gamma downregulates CFTR gene expression in epithelial cells." American Journal of Physiology-Cell Physiology 267, no. 5 (November 1, 1994): C1398—C1404. http://dx.doi.org/10.1152/ajpcell.1994.267.5.c1398.

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Cystic fibrosis (CF) is caused by mutations in the CF transmembrane conductance regulator (CFTR) gene, resulting in defective transepithelial Cl- transport. The regulation of CF gene expression is not fully understood. We report that interferon-gamma (IFN-gamma), but not IFN-alpha or -beta, downregulates CFTR mRNA levels in two colon-derived epithelial cell lines, HT-29 and T84, in a time- and concentration (from 0.1 IU/ml)-dependent manner. IFN-gamma has no effect on the transcription rate of the CFTR gene but reduces CFTR mRNA half-life, indicating that it exerts a posttranscriptional regulation of CFTR expression, at least partly, through destabilization of the transcripts. Cells treated with IFN-gamma contain subnormal amounts of 165-kDa CFTR protein. Assays of adenosine 3',5'-cyclic monophosphate-stimulated 36Cl- efflux and whole cell currents show that CFTR function is diminished in IFN-gamma-treated cells. IFN-gamma and tumor necrosis factor-alpha synergistically reduce CFTR gene expression. Our results suggest that production of these cytokines in response to bacterial infections and inflammatory disorders may alter transmembrane Cl- transport.
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45

Utay, Netanya Sandler, and Daniel C. Douek. "Interferons and HIV Infection: The Good, the Bad, and the Ugly." Pathogens and Immunity 1, no. 1 (July 6, 2016): 107. http://dx.doi.org/10.20411/pai.v1i1.125.

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Whether type I interferons (IFNs) hinder or facilitate HIV disease progression is controversial. Type I IFNs induce the production of restriction factors that protect against mucosal HIV/SIV acquisition and limit virus replication once systemic infection is established. However, type I IFNs also increase systemic immune activation, a predictor of poor CD4+ T-cell recovery and progression to AIDS, and facilitate production and recruitment of target CD4+ T cells. In addition, type I IFNs induce CD4+ T-cell apoptosis and limit antigen-specific CD4+ and CD8+ T-cell responses. The outcomes of type I IFN signaling may depend on the timing of IFN-stimulated gene upregulation relative to HIV exposure and infection, local versus systemic type I IFN-stimulated gene expression, and the subtype of type I IFN evaluated. To date, most interventional studies have evaluated IFNa2 administration largely in chronic HIV infection, and few have evaluated the effects on tissues or the HIV reservoir. Thus, whether the effect of type I IFN signaling on HIV disease is good, bad, or so complicated as to be ugly remains a topic of hot debate.
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46

Rosenbauer, Frank, Jeffrey F. Waring, John Foerster, Marcus Wietstruk, Dieter Philipp, and Ivan Horak. "Interferon Consensus Sequence Binding Protein and Interferon Regulatory Factor-4/Pip Form a Complex That Represses the Expression of the Interferon-Stimulated Gene-15 in Macrophages." Blood 94, no. 12 (December 15, 1999): 4274–81. http://dx.doi.org/10.1182/blood.v94.12.4274.

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Abstract Interferon consensus sequence binding protein (ICSBP), a transcription factor of the interferon (IFN) regulatory factor (IRF) family, binds to the IFN-stimulated response element (ISRE) in the regulatory region of IFNs and IFN-stimulated genes (ISG). To identify target genes, which are deregulated by an ICSBP null-mutation in mice (ICSBP−/−), we have analyzed transcription of an ISRE-bearing gene, ISG15. We have found that although ISG15 expression is unchanged in B cells, it is upregulated in macrophages from ICSBP−/− mice. Three factors, ICSBP, IRF-2, and IRF-4/Pip interact with the ISRE in B cells, however only ICSBP and IRF-4/Pip were found to bind this sequence in macrophages of wild-type mice. Although IRF-4 was considered to be a lymphoid-specific factor, we provide evidence for its role in macrophage gene regulation. Our results suggest that the formation of cell-type–specific heteromeric complexes between individual IRFs plays a crucial role in regulating IFN responses.
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47

Rosenbauer, Frank, Jeffrey F. Waring, John Foerster, Marcus Wietstruk, Dieter Philipp, and Ivan Horak. "Interferon Consensus Sequence Binding Protein and Interferon Regulatory Factor-4/Pip Form a Complex That Represses the Expression of the Interferon-Stimulated Gene-15 in Macrophages." Blood 94, no. 12 (December 15, 1999): 4274–81. http://dx.doi.org/10.1182/blood.v94.12.4274.424k05_4274_4281.

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Interferon consensus sequence binding protein (ICSBP), a transcription factor of the interferon (IFN) regulatory factor (IRF) family, binds to the IFN-stimulated response element (ISRE) in the regulatory region of IFNs and IFN-stimulated genes (ISG). To identify target genes, which are deregulated by an ICSBP null-mutation in mice (ICSBP−/−), we have analyzed transcription of an ISRE-bearing gene, ISG15. We have found that although ISG15 expression is unchanged in B cells, it is upregulated in macrophages from ICSBP−/− mice. Three factors, ICSBP, IRF-2, and IRF-4/Pip interact with the ISRE in B cells, however only ICSBP and IRF-4/Pip were found to bind this sequence in macrophages of wild-type mice. Although IRF-4 was considered to be a lymphoid-specific factor, we provide evidence for its role in macrophage gene regulation. Our results suggest that the formation of cell-type–specific heteromeric complexes between individual IRFs plays a crucial role in regulating IFN responses.
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48

Burska, A., J. Rodriguez Carrio, P. G. Conaghan, W. A. Dik, R. Biesen, M. L. Eloranta, G. Cavalli, et al. "POS0370 TYPE I INTERFERON PATHWAY ASSAYS IN PATIENTS WITH RHEUMATIC AND MUSCULOSKELETAL DISEASES - SYSTEMATIC LITERATURE REVIEW (SLR) AND DEVELOPMENT OF CONSENSUS TERMINOLOGY FROM A EULAR TASKFORCE." Annals of the Rheumatic Diseases 80, Suppl 1 (May 19, 2021): 415. http://dx.doi.org/10.1136/annrheumdis-2021-eular.3788.

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Background:The interferon (IFN) pathway is a complex system with multiple proteins and diverse downstream effects on gene and protein expression. IFNs have been implicated in multiple RMDs. Despite significant potential, IFN assays have not progressed into clinical practice.Objectives:To perform a SLR on IFN assays in RMDs and propose a consensus terminology.Methods:OvidMedline, Embase and Web of Science were searched for reports of IFN and RMDs up to October 2019. Information about the properties of assays measuring type I IFN and measures of truth were extracted and summarised. Terminology was agreed through an interactive consensus process with reference to the existing evidence.Results:10037 abstracts were identified. 275 fulfilled eligibility criteria, and were used for data extraction. Some used more than one technique to measure IFN-I pathway activation. Hence, 275 papers generated data on 393 methods. There was great heterogeneity in the methods used and presentation of results. IFN-I pathway activation was measured using: qPCR (n=121), immunoassays (n=101), microarray (n=69), reporter cell assay (n=38), DNA methylation (n=14), flow cytometry (n=14), cytopathic effect assay (n=11), RNA sequencing (n=9), Plaque reduction assay (n=8), Nanostring (n=5), bisulphite sequencing (n=3). All papers fulfilled Face Validity. Due to lack of gold standard for IFN-I pathway activation, evidence of criterion validity was variable. Concurrent validity was presented for n=150 assays. The terminology used to describe aspects of type I IFN pathway activation was not consistent, so a consensus terminology for IFN research (Table 1) was proposed by the taskforce.Table 1.Consensus terminologyTermAbbreviationDefinitionInterferonIFNProteins with anti-viral activity; IFNs are mediators of an anti-viral response. They belong to the Type I, Type II and Type III IFN families.Type I interferonIFN-IThe IFNs alpha, beta, omega, kappa, epsilon, secreted by any nucleated cell, and binding to the IFNAR, which is expressed on any nucleated cell.Type II interferonIFN-IIIFN gamma, mostly secreted by T cells, binding to the IFNGR, which is expressed on most leucocytes.Type III interferonIFN-IIIIFN lambda, which are structurally more similar to IL-10 but share downstream signalling and gene expression with IFN-I.Interferon-stimulated genesISGsGenes whose expression is known to be upregulated by any kind of IFN. Individual ISGs may not exclusively represent Type I IFN pathway activation.Type I Interferon pathway activationAny evidence for function of the components of the Type I IFN pathway. This includes: secretion of a Type I IFN protein, binding to the IFNAR, initiation of JAK/STAT signalling pathways, expression of IFN-stimulated genes, expression of IFN-stimulated proteins.Type I interferon pathway assayAn assay measuring one or more components of the Type I IFN pathway at a molecular or functional level.Interferon stimulated gene expression signatureA qualitative description of coordinated expression of a set of ISGs that is indicative of Type I IFN pathway activation.Interferon stimulated gene expression scoreA quantitative variable derived from expression of a defined set of ISGs that is indicative of Type I IFN pathway activation.Interferon stimulated protein scoreA variable derived from expression of a defined set of soluble biomarkers known to be upregulated by IFN, although not specific for Type I IFN.InterferonopathyMonogenic diseases in which there is constitutive Type I IFN pathway activation with a causal role in pathology. The clinical picture may resemble rheumatic musculoskeletal diseases. However, most diseases with IFN pathway activation are not Interferonopathies.Conclusion:Diverse methods have been reported as IFN assays and these differ in what elements of type IFN-I pathway activation they measure. The taskforce consensus terminology on type I IFN reporting should be considered for research and clinical applications.Disclosure of Interests:Agata Burska: None declared, Javier Rodriguez Carrio: None declared, Philip G Conaghan: None declared, Willem A Dik: None declared, Robert Biesen: None declared, Maija-leena Eloranta: None declared, Giulio Cavalli: None declared, Marianne Visser: None declared, Dimitrios Boumpas: None declared, George Bertsias: None declared, Marie Wahren-Herlenius: None declared, Jan Rehwinkel: None declared, Marie-Louise Frémond: None declared, Mary K. Crow Consultant of: AstraZeneca, Bristol Meyers Squibb, Lilly, Shannon Pharmaceuticals, Grant/research support from: Gilead, Lars Ronnblom Consultant of: AstraZeneca, Edward Vital Speakers bureau: GSK, Consultant of: AURINIA, SANDOZ, GSK, AstraZeneca, Roche, Modus, Grant/research support from: AstraZeneca, Marjan Versnel: None declared
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49

Hodge, Deborah L., Alfredo Martinez, John G. Julias, Lynn S. Taylor, and Howard A. Young. "Regulation of Nuclear Gamma Interferon Gene Expression by Interleukin 12 (IL-12) and IL-2 Represents a Novel Form of Posttranscriptional Control." Molecular and Cellular Biology 22, no. 6 (March 15, 2002): 1742–53. http://dx.doi.org/10.1128/mcb.22.6.1742-1753.2002.

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ABSTRACT Posttranscriptional control of gamma interferon (IFN-γ) gene expression has not been extensively studied and is poorly understood. Our work describes a posttranscriptional mechanism that modulates IFN-γ mRNA expression in stimulated natural killer (NK) cells through nuclear retention of the IFN-γ mRNA. This is evidenced by the elevated and sustained nuclear accumulation of both precursor and processed IFN-γ mRNAs in NK cells stimulated with interleukin-12 (IL-12). The elevated nuclear mRNA accumulation persists long after transcriptional activity has subsided and the rate of cytoplasmic IFN-γ mRNA accumulation has dropped. The IL-12-induced nuclear retention of the IFN-γ mRNA prevails until a secondary cytokine stimulus is received. The secondary stimulus, which is initiated by IL-2, mediates transcription-independent movement of the nuclear IFN-γ mRNA. Concurrent with the nucleocytoplasmic movement of the IFN-γ mRNA, we have observed increases in the amount of processed nuclear IFN-γ mRNA that are greater than that seen for the unprocessed IFN-γ mRNA. The increase in processed IFN-γ mRNA appears to be due to increased mRNA stability which then promotes increased nucleocytoplasmic shuttling of the mature IFN-γ mRNA. These data support a model whereby mobilization of nuclear IFN-γ mRNA stores allows NK cells to rapidly and robustly respond to secondary cytokine activators in a transcription-independent manner, thus shortening the time for overall cellular response to inflammatory signals.
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50

Lenschow, Deborah J., Nadia V. Giannakopoulos, Lacey J. Gunn, Christine Johnston, Andy K. O'Guin, Robert E. Schmidt, Beth Levine, and Herbert W. Virgin. "Identification of Interferon-Stimulated Gene 15 as an Antiviral Molecule during Sindbis Virus Infection In Vivo." Journal of Virology 79, no. 22 (November 15, 2005): 13974–83. http://dx.doi.org/10.1128/jvi.79.22.13974-13983.2005.

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ABSTRACT The innate immune response, and in particular the alpha/beta interferon (IFN-α/β) system, plays a critical role in the control of viral infections. Interferons α and β exert their antiviral effects through the induction of hundreds of interferon-induced (or -stimulated) genes (ISGs). While several of these ISGs have characterized antiviral functions, their actions alone do not explain all of the effects mediated by IFN-α/β. To identify additional IFN-induced antiviral molecules, we utilized a recombinant chimeric Sindbis virus to express selected ISGs in IFN-α/β receptor (IFN-α/βR)−/− mice and looked for attenuation of Sindbis virus infection. Using this approach, we identified a ubiquitin homolog, interferon-stimulated gene 15 (ISG15), as having antiviral activity. ISG15 expression protected against Sindbis virus-induced lethality and decreased Sindbis virus replication in multiple organs without inhibiting the spread of virus throughout the host. We establish that, much like ubiquitin, ISG15 requires its C-terminal LRLRGG motif to form intracellular conjugates. Finally, we demonstrate that ISG15's LRLRGG motif is also required for its antiviral activity. We conclude that ISG15 can be directly antiviral.
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