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Journal articles on the topic 'BRRF1'

Author: Grafiati
Published: 4 June 2021
Last updated: 12 February 2022

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1

Segouffin-Cariou, Carine, Géraldine Farjot, Alain Sergeant, and Henri Gruffat. "Characterization of the Epstein–Barr virus BRRF1 gene, located between early genes BZLF1 and BRLF1." Microbiology 81, no. 7 (July 1, 2000): 1791–99. http://dx.doi.org/10.1099/0022-1317-81-7-1791.

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The switch from latency to a productive cycle in Epstein–Barr virus (EBV)-infected B cells proliferating in vitro is thought to be due to the transcriptional activation of two viral genes, BZLF1 and BRLF1, encoding two transcription factors called EB1 and R respectively. However, a third gene, BRRF1 is contained in the BZLF1/BRLF1 locus, overlapping with BRLF1 but in inverse orientation. We have characterized the 5′ end of the BRRF1 mRNA and the promoter, PNa, at which BRRF1 pre-mRNA is initiated. We show that although a single BRRF1 mRNA species is induced by 12-O-tetradecanoylphorbol 13-acetate/sodium butyrate in several EBV-infected B cell lines, in Akata cells treated with anti-IgG two BRRF1 mRNAs can be detected. Transcription initiated at the BRRF1 promoter was activated by EB1 but not by R, and EB1-binding sites which contribute to the EB1-activated transcription have been mapped to between positions −469 and +1. A 34 kDa protein could be translated from the BRRF1 mRNA both in vitro and in vivo, and was found predominantly in the nucleus of HeLa cells transfected with a BRRF1 expression vector. Thus there are three promoters in the region of the EBV chromatin containing the BZLF1/BRLF1 genes, two of which, PZ and PNa, potentially share regulatory elements.
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2

Hong, Gregory K., Henri-Jacques Delecluse, Henri Gruffat, Thomas E. Morrison, Wen-Hai Feng, Alain Sergeant, and Shannon C. Kenney. "The BRRF1 Early Gene of Epstein-Barr Virus Encodes a Transcription Factor That Enhances Induction of Lytic Infection by BRLF1." Journal of Virology 78, no. 10 (May 15, 2004): 4983–92. http://dx.doi.org/10.1128/jvi.78.10.4983-4992.2004.

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ABSTRACT The switch from the latent to the lytic form of Epstein-Barr virus (EBV) infection is mediated by expression of the viral immediate-early (IE) proteins, BZLF1 (Z) and BRLF1 (R). An EBV early protein, BRRF1 (Na), is encoded by the opposite strand of the BRLF1 intron, but the function of this nuclear protein in the viral life cycle is unknown. Here we demonstrate that Na enhances the R-mediated induction of lytic EBV infection in 293 cells latently infected with a recombinant EBV (R-KO) defective for the expression of both R and Na. Na also enhances R-induced lytic infections in a gastric carcinoma line (AGS) carrying the R-KO virus, although it has no effect in a Burkitt lymphoma line (BL-30) stably infected with the same mutant virus. We show that Na is a transcription factor that increases the ability of R to activate Z expression from the R-KO viral genome in 293 cells and that Na by itself activates the Z promoter (Zp) in EBV-negative cells. Na activation of Zp requires a CRE motif (ZII), and a consensus CRE motif is sufficient to transfer Na responsiveness to the heterologous E1b promoter. Furthermore, we show that Na enhances the transactivator function of a Gal4-c-Jun fusion protein but does not increase the transactivator function of other transcription factors (including ATF-1, ATF-2, and CREB) known to bind CRE motifs. Na expression in cells results in increased levels of a hyperphosphorylated form of c-Jun, suggesting a mechanism by which Na activates c-Jun. Our results indicate that Na is a transcription factor that activates the EBV Zp IE promoter through its effects on c-Jun and suggest that Na cooperates with BRLF1 to induce the lytic form of EBV infection in certain cell types.
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3

Hagemeier, S. R., E. A. Barlow, A. A. Kleman, and S. C. Kenney. "The Epstein-Barr Virus BRRF1 Protein, Na, Induces Lytic Infection in a TRAF2- and p53-Dependent Manner." Journal of Virology 85, no. 9 (February 16, 2011): 4318–29. http://dx.doi.org/10.1128/jvi.01856-10.

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4

Cornaby, Caleb, Jillian L. Jafek, Cameron Birrell, Vera Mayhew, Lauren Syndergaard, Jeffrey Mella, Wesley Cheney, and Brian D. Poole. "EBI2 expression in B lymphocytes is controlled by the Epstein–Barr virus transcription factor, BRRF1 (Na), during viral infection." Journal of General Virology 98, no. 3 (March 1, 2017): 435–46. http://dx.doi.org/10.1099/jgv.0.000660.

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5

Vouri, Mikaela, Audrey Mercier, Patricia Benites Goncalves da Silva, Konstantin Okonechnikov, Antoine Forget, Hua Yu, Anais Chivet, et al. "MBRS-51. MUTATIONS IN BRPF1 FOUND IN SHH MEDULLOBLASTOMA PREVENT INTERACTION WITH TP53 AND LEADS TO RADIORESISTANCE IN VITRO." Neuro-Oncology 22, Supplement_3 (December 1, 2020): iii406—iii407. http://dx.doi.org/10.1093/neuonc/noaa222.558.

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Abstract Medulloblastoma (MB) is one of the most common pediatric tumors in children. Among them, SHH subgroups of MB (MBSHH) is characterized by constitutive activation of SHH pathway. Somatic mutations in BRPF1, a chromatin modifier, is found in more than 5% of MBSHH and accounts for almost 20% of adult MBSHH but its potential role in MBSHH pathophysiology is still unknown. In this study, we first examined the function of Brpf1 on pro-tumorigenic features of MBSHH and evaluated molecular pathways regulated by Brpf1 using Brpf1floxed::Atoh1-Cre conditional knockout mice, in which Brpf1 is conditionally deleted in cerebellar granule neuron progenitors (GNPs). While RNA-seq analysis on GNPs from Brpf1 WT and KO mice showed significant differences in the pathways related with cell cycle and cell death, deletion of Brpf1 did not cause acceleration of tumorigenesis in the Ptch1 heterozygous tumor-prone. Background: Co-immunoprecipitation followed by mass spectrometry analysis identified interaction partners of BRPF1 including MOZ, MORF and ING5, known partners of BRPF1. Gene ontology analysis also depicted pathways important for cell cycle progression, cell death and response to DNA damage. Consistent with these observations, TP53 was identified as a novel co-factor of BRPF1. Of note, some of MBSHH-relevant BRPF1 mutations prevented interaction with TP53. According to the previous finding that cytosolic TP53 is required for apoptotic cell death, GNPs expressing the BRPF1-R600X mutant gene exhibited the resistance to irradiation-induced cell death. In conclusion, our data revealed that BRPF1 mutants found in MBSHH could prevent the complex formation with TP53, leading to enhanced resistance to cell apoptosis.
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6

Darr, Catherine Dayle, Amy Mauser, and Shannon Kenney. "Epstein-Barr Virus Immediate-Early Protein BRLF1 Induces the Lytic Form of Viral Replication through a Mechanism Involving Phosphatidylinositol-3 Kinase Activation." Journal of Virology 75, no. 13 (July 1, 2001): 6135–42. http://dx.doi.org/10.1128/jvi.75.13.6135-6142.2001.

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ABSTRACT Expression of the Epstein-Barr virus (EBV) immediate-early (IE) protein BRLF1 induces the lytic form of viral replication in most EBV-positive cell lines. BRLF1 is a transcriptional activator that binds directly to a GC-rich motif present in some EBV lytic gene promoters. However, BRLF1 activates transcription of the other IE protein, BZLF1, through an indirect mechanism which we previously showed to require activation of the stress mitogen-activated protein kinases. Here we demonstrate that BRLF1 activates phosphatidylinositol-3 (PI3) kinase signaling in host cells. We show that the specific PI3 kinase inhibitor, LY294002, completely abrogates the ability of a BRLF1 adenovirus vector to induce the lytic form of EBV infection, while not affecting lytic infection induced by a BZLF1 adenovirus vector. Furthermore, we demonstrate that the requirement for PI3 kinase activation in BRLF1-induced transcriptional activation is promoter dependent. BRLF1 activation of the SM early promoter (which occurs through a direct binding mechanism) does not require PI3 kinase activation, whereas activation of the IE BZLF1 and early BMRF1 promoters requires PI3 kinase activation. Thus, there are clearly two separate mechanisms by which BRLF1 induces transcriptional activation.
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7

Swenson, Jennifer J., Elizabeth Holley-Guthrie, and Shannon C. Kenney. "Epstein-Barr Virus Immediate-Early Protein BRLF1 Interacts with CBP, Promoting Enhanced BRLF1 Transactivation." Journal of Virology 75, no. 13 (July 1, 2001): 6228–34. http://dx.doi.org/10.1128/jvi.75.13.6228-6234.2001.

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ABSTRACT The Epstein-Barr virus (EBV) immediate-early protein BRLF1 is a transcriptional activator that mediates the switch from latent to lytic viral replication. Many transcriptional activators function, in part, due to an interaction with histone acetylases, such as CREB-binding protein (CBP). Here we demonstrate that BRLF1 interacts with the amino and carboxy termini of CBP and that multiple domains of the BRLF1 protein are necessary for this interaction. Furthermore, we show that the interaction between BRLF1 and CBP is important for BRLF1-induced activation of the early lytic EBV gene SM in Raji cells.
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8

Ningsih, Tri Yulia, Daniel Joko Wahyono, and Nur Signa Aini Gumilas. "Deteksi Gen Litik BRLF1 Epstein-Barr Virus pada Penderita Karsinoma Nasofaring." Biosfera 35, no. 1 (January 10, 2018): 29. http://dx.doi.org/10.20884/1.mib.2018.35.1.517.

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Rosenmuller fossa. Epithelial malignancy is often found in Chinese populations and Southeast Asia including Indonesia. Undifferentiated nasopharyngeal carcinoma (NPC WHO-3) type is 100% associated with Epstein-Barr virus (EBV) infection. Bam-HI R Leftward Reading Frame 1 (BRLF1) lytic gene has an important function as a transition mediator of latent phase to the lytic phase in EBV cycle. Detection of BRLF1 gene by PCR can be used for NPC diagnosis. The aim of this study is to identify BRLF1 lytic genes as molecular markers of Epstein-Barr virus in nasopharyngeal carcinoma patients with conventional PCR method and to determine the sensitivity of conventional PCR method to detect BRLF1 gene. The research design was cross sectional study. A total of 22 DNA samples were isolated from venous blood of NPC patients from RSUD Prof dr Margono Soekarjo, Purwokerto with informed consent. BRLF1 gene identification is done with conventional PCR technique. The results of this research showed that BRLF1 genes as molecular markers lytic cycle of Epstein-Barr virus in nasopharyngeal carcinoma patients can be identified conventional PCR technique that will produced DNA 157 bp. BRLF1 gene was detected in 16 samples (72.73%) of 22 samples of this study.
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9

Yan, Kezhi, Justine Rousseau, Keren Machol, Laura A. Cross, Katherine E. Agre, Cynthia Forster Gibson, Anne Goverde, et al. "Deficient histone H3 propionylation by BRPF1-KAT6 complexes in neurodevelopmental disorders and cancer." Science Advances 6, no. 4 (January 2020): eaax0021. http://dx.doi.org/10.1126/sciadv.aax0021.

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Lysine acetyltransferase 6A (KAT6A) and its paralog KAT6B form stoichiometric complexes with bromodomain- and PHD finger-containing protein 1 (BRPF1) for acetylation of histone H3 at lysine 23 (H3K23). We report that these complexes also catalyze H3K23 propionylation in vitro and in vivo. Immunofluorescence microscopy and ATAC-See revealed the association of this modification with active chromatin. Brpf1 deletion obliterates the acylation in mouse embryos and fibroblasts. Moreover, we identify BRPF1 variants in 12 previously unidentified cases of syndromic intellectual disability and demonstrate that these cases and known BRPF1 variants impair H3K23 propionylation. Cardiac anomalies are present in a subset of the cases. H3K23 acylation is also impaired by cancer-derived somatic BRPF1 mutations. Valproate, vorinostat, propionate and butyrate promote H3K23 acylation. These results reveal the dual functionality of BRPF1-KAT6 complexes, shed light on mechanisms underlying related developmental disorders and various cancers, and suggest mutation-based therapy for medical conditions with deficient histone acylation.
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10

Wu, Teng, Dongkun Zhang, Mingen Lin, Lihong Yu, Ting Dai, Shuai Li, Fenghai Yu, Lei Lu, Liling Zheng, and Shuping Zhong. "Exploring the Role and Mechanism of pAMPKα-Mediated Dysregulation of Brf1 and RNA Pol III Genes." Oxidative Medicine and Cellular Longevity 2021 (April 20, 2021): 1–15. http://dx.doi.org/10.1155/2021/5554932.

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TF IIB-related factor 1 (Brf1) is a key transcription factor of RNA polymerase III (Pol III) genes. Our early studies have demonstrated that Brf1 and Pol III genes are epigenetically modulated by histone H3 phosphorylation. Here, we have further investigated the relationship of the abnormal expression of Brf1 with a high level of phosphorylated AMPKα (pAMPKα) and explored the role and molecular mechanism of pAMPKα-mediated dysregulation of Brf1 and Pol III genes in lung cancer. Brf1 is significantly overexpressed in lung cancer cases. The cases with high Brf1 expression display short overall survival times. Elevation of Brf1 expression is accompanied by a high level of pAMPKα. Brf1 and pAMPKα colocalize in nuclei. Further analysis indicates that the carcinogen MNNG induces pAMPKα to upregulate Brf1 expression, resulting in the enhancement of Pol III transcription. In contrast, inhibiting pAMPKα decreases cellular levels of Brf1, resulting in the reduction of Pol III gene transcription to attenuate the rates of cell proliferation and colony formation of lung cancer cells. These outcomes demonstrate that high Brf1 expression reveals a worse prognosis in lung cancer patients. pAMPKα-mediated dysregulation of Brf1 and Pol III genes plays important roles in cell proliferation, colony formation, and tumor development of lung cancer. Brf1 may be a biomarker for establishing the prognosis of lung cancer. It is a new mechanism that pAMPKα mediates dysregulation of Brf1 and Pol III genes to promote lung cancer development.
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11

Lubula, Mulu Y., Amanda Poplawaski, and Karen C. Glass. "Crystallization and preliminary X-ray diffraction analysis of the BRPF1 bromodomain in complex with its H2AK5ac and H4K12ac histone-peptide ligands." Acta Crystallographica Section F Structural Biology Communications 70, no. 10 (September 25, 2014): 1389–93. http://dx.doi.org/10.1107/s2053230x14018433.

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The bromodomain-PHD finger protein 1 (BRPF1) is an essential subunit of the monocytic leukemia zinc (MOZ) histone acetyltransferase (HAT) complex and is required for complex formation and enzymatic activation. BRPF1 contains a structurally conserved bromodomain, which recognizes specific acetyllysine residues on histone proteins. The MOZ HAT plays a direct role in hematopoiesis, and deregulation of its activity is linked to the development of acute myeloid leukemia. However, the molecular mechanism of histone-ligand recognition by the BRPF1 bromodomain is currently unknown. The 117-amino-acid BRPF1 bromodomain was overexpressed inEscherichia coliand purified to homogeneity. Crystallization experiments of the BRPF1 bromodomain in complex with its H4K12ac and H2AK5ac histone ligands yielded crystals that were suitable for high-resolution X-ray diffraction analysis. The BRPF1 bromodomain–H4K12ac crystals belonged to the tetragonal space groupP43212, with unit-cell parametersa= 75.1,b= 75.1,c= 86.3 Å, and diffracted to a resolution of 1.94 Å. The BRPF1 bromodomain–H2AK5ac crystals grew in the monoclinic space groupP21, with unit-cell parametersa= 60.9,b= 55.6,c= 82.1 Å, β = 93.6°, and diffracted to a resolution of 1.80 Å. Complete data sets were collected from both crystal forms using synchrotron radiation on beamline X29 at Brookhaven National Laboratory (BNL).
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Liao, Yanling, Robyn D. Moir, and Ian M. Willis. "Interactions of Brf1 Peptides with the Tetratricopeptide Repeat-Containing Subunit of TFIIIC Inhibit and Promote Preinitiation Complex Assembly." Molecular and Cellular Biology 26, no. 16 (August 15, 2006): 5946–56. http://dx.doi.org/10.1128/mcb.00689-06.

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ABSTRACT The binding of Brf1 to the tetratricopeptide repeat (TPR)-containing transcription factor IIIC (TFIIIC) subunit (Tfc4) represents a rate-limiting step in the ordered assembly of the RNA polymerase III initiation factor TFIIIB. Tfc4 contains multiple binding sites for Brf1 within its amino terminus and adjacent TPR arrays, but the access of Brf1 to these sites is limited by autoinhibition. Moreover, the Brf1 binding sites in Tfc4 overlap with sites important for the subsequent recruitment of another TFIIIB subunit, Bdp1, implying that repositioning of Brf1 is required after its initial interaction with Tfc4. As a starting point for dissecting the steps in TFIIIC-directed assembly of TFIIIB, we conducted yeast two-hybrid screens of Brf1 peptide libraries against different TPR-containing Tfc4 fragments. Short, biochemically active peptides were identified in three distinct regions of Brf1. Two peptides defined conserved but distal regions of Brf1 that participate in stable binding of Brf1 to TFIIIC-DNA. Remarkably, a third peptide that binds specifically to TPR6-9 of Tfc4 was found to promote the formation of both TFIIIC-DNA and Brf1-TFIIIC-DNA complexes and to reduce the mobility of these complexes in native gels. The data are consistent with this peptide causing a conformational change in TFIIIC that overcomes Tfc4 autoinhibition of Brf1 binding and suggest a structural model for the Brf1-Tfc4 interaction.
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13

Adamson, Amy, and Dennis LaJeunesse. "A Study of Epstein-Barr Virus BRLF1 Activity in aDrosophilaModel System." Scientific World Journal 2012 (2012): 1–9. http://dx.doi.org/10.1100/2012/347597.

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Epstein-Barr virus, a member of the herpesvirus family, infects a large majority of the human population and is associated with several diseases, including cancer. We have createdDrosophilamodel systems to study the interactions between host cellular proteins and the Epstein-Barr virus (EBV) immediate-early genes BRLF1 and BZLF1. BRLF1 and BZLF1 function as transcription factors for viral transcription and are also potent modifiers of host cell activity. Here we have used our model systems to identify host cell genes whose proteins modulate BRLF1 and BZLF1 functions. Via ourGMR-Rmodel system, we have found that BRLF1 expression results in overproliferation of fly tissue, unlike BZLF1, and does so through the interaction with known tumor suppressor genes. Through an additional genetic screen, we have identified severalDrosophilagenes, with human homologs, that may offer further insights into the pathways that BRLF1 interacts with in order to promote EBV replication.
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Ullah, Mukta, Nadine Pelletier, Lin Xiao, Song Ping Zhao, Kainan Wang, Cindy Degerny, Soroush Tahmasebi, et al. "Molecular Architecture of Quartet MOZ/MORF Histone Acetyltransferase Complexes." Molecular and Cellular Biology 28, no. 22 (September 15, 2008): 6828–43. http://dx.doi.org/10.1128/mcb.01297-08.

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ABSTRACT The monocytic leukemia zinc finger protein MOZ and the related factor MORF form tetrameric complexes with ING5 (inhibitor of growth 5), EAF6 (Esa1-associated factor 6 ortholog), and the bromodomain-PHD finger protein BRPF1, -2, or -3. To gain new insights into the structure, function, and regulation of these complexes, we reconstituted them and performed various molecular analyses. We found that BRPF proteins bridge the association of MOZ and MORF with ING5 and EAF6. An N-terminal region of BRPF1 interacts with the acetyltransferases; the enhancer of polycomb (EPc) homology domain in the middle part binds to ING5 and EAF6. The association of BRPF1 with EAF6 is weak, but ING5 increases the affinity. These three proteins form a trimeric core that is conserved from Drosophila melanogaster to humans, although authentic orthologs of MOZ and MORF are absent in invertebrates. Deletion mapping studies revealed that the acetyltransferase domain of MOZ/MORF is sufficient for BRPF1 interaction. At the functional level, complex formation with BRPF1 and ING5 drastically stimulates the activity of the acetyltransferase domain in acetylation of nucleosomal histone H3 and free histones H3 and H4. An unstructured 18-residue region at the C-terminal end of the catalytic domain is required for BRPF1 interaction and may function as an “activation lid.” Furthermore, BRPF1 enhances the transcriptional potential of MOZ and a leukemic MOZ-TIF2 fusion protein. These findings thus indicate that BRPF proteins play a key role in assembling and activating MOZ/MORF acetyltransferase complexes.
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15

Estania, Andreanne Poppy, Hidayat Sulistyo, and Daniel Joko Wahyono. "Ekspresi Relatif mRNA BRLF1 Epstein-Barr Virus dari Biopsi Jaringan Tumor dalam Blok Parafin sebagai Petanda Biologi Patogenesis Karsinoma Nasofaring." Biosfera 34, no. 2 (September 21, 2017): 59. http://dx.doi.org/10.20884/1.mib.2017.34.2.409.

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Karsinoma nasofaring (KNF) merupakan tumor ganas pada sel epitel nasofaring dan merupakan penyakit multifaktor yang bersifat endemik. Tipe KNF tidak berdiferensiasi (KNF WHO-3) telah terbukti konsisten dengan infeksi EBV. Gen litik BRLF1 berperan sebagai mediator transisi dari fase laten menjadi litik. Pengukuran aktivitas mRNA EBV di lokasi tumor primer perlu dilakukan karena lebih mencerminkan patogenesis KNF yang sesungguhnya dari pada diagnosis serologi dan pengukuran DNA EBV di sirkulasi darah. Penelitian ini bertujuan untuk mengetahui nilai ekspresi relatif mRNA BRLF1 Epstein-Barr Virus pada beberapa tingkat stadium tumor penderita KNF sebagai petanda biologi potensial dalam patogenesis KNF. Metode penelitian yang digunakan adalah metode deskriptif yang berbentuk studi seran lintang. Sampel penelitian ini adalah biopsi jaringan tumor dalam blok parafin penderita KNF sebanyak 24 sampel. Sampel tersebut telah didiagnosis pasti sebagai KNF WHO-3 dari hasil pemeriksaan Patologi Anatomi pada Poli Patologi Anatomi, RSUD Prof. Dr. Margono Soekarjo, Purwokerto serta memenuhi kriteria inklusi sampel. Analisis statistik dilakukan untuk membandingkan ekspresi relatif mRNA BRLF1 stadium yang berbeda. Nilai ekspresi relatif mRNA BRLF1 EBV pada 24 sampel KNF berkisar 99,04415959-1097,496026. Hasil analisis statistik menunjukkan nilai ekspresi relatif mRNA BRLF1 EBV pada stadium awal (n = 5; 544,72420 + 142,614733) lebih tinggi 1,8 kali dibandingkan dengan stadium lanjut (n = 17; 395,68612 + 293,172201), namun peningkatan ekspresi relatif mRNA BRLF1 EBV tidak bermakna secara statistik karena didapatkan nilai p=0,130 (p>0,05). Oleh karena itu, ekspresi relatif mRNA BRLF1 EBV dari biopsi jaringan tumor dalam blok parafin tidak berpotensi sebagai petanda biologi molekul patogenesis KNF, khususnya progresivitas tumor pada stadium lanjut KNF.
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Feng, Wen-hai, Eva Westphal, Amy Mauser, Nancy Raab-Traub, Margaret L. Gulley, Pierre Busson, and Shannon C. Kenney. "Use of Adenovirus Vectors Expressing Epstein-Barr Virus (EBV) Immediate-Early Protein BZLF1 or BRLF1 To Treat EBV-Positive Tumors." Journal of Virology 76, no. 21 (November 1, 2002): 10951–59. http://dx.doi.org/10.1128/jvi.76.21.10951-10959.2002.

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ABSTRACT The Epstein-Barr virus (EBV) genome is present in a variety of tumor types, including virtually all undifferentiated nasopharyngeal carcinomas (NPC) and a portion of gastric carcinomas. The uniform presence of the EBV genome in certain tumors (versus only a very small number of normal B cells) suggests that novel therapies which specifically target EBV-positive cells for destruction might be effective for treating such tumors. Although the great majority of EBV-positive tumor cells are infected with one of the latent forms of EBV infection, expression of either viral immediate-early protein (BZLF1 or BRLF1) is sufficient to convert the virus to the lytic form of infection. Induction of the lytic form of EBV infection could potentially result in death of the tumor cell. Here we have examined the efficacy of adenovirus vectors expressing the BZLF1 or BRLF1 proteins for treatment of EBV-positive epithelial tumors. The BZLF1 and BRLF1 vectors induced preferential killing of EBV-positive, versus EBV-negative, gastric carcinoma cells in vitro. Infection of C18 NPC tumors (grown in nude mice) with either the BZLF1 or BRLF1 vector, but not a control adenovirus vector, induced expression of early lytic EBV genes in tumor cells. Injection of C18 tumors with the BZLF1 or BRLF1 adenovirus vector, but not the control vector, also significantly inhibited growth of the tumors in nude mice. The addition of ganciclovir did not significantly affect the antitumor effect of the BZLF1 and BRLF1 adenovirus vectors. These results suggest a potential cancer therapy against EBV-related tumors.
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Swenson, Jennifer J., Amy E. Mauser, William K. Kaufmann, and Shannon C. Kenney. "The Epstein-Barr Virus Protein BRLF1 Activates S Phase Entry through E2F1 Induction." Journal of Virology 73, no. 8 (August 1, 1999): 6540–50. http://dx.doi.org/10.1128/jvi.73.8.6540-6550.1999.

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ABSTRACT The Epstein-Barr Virus (EBV) immediate-early protein BRLF1 is one of two transactivators which mediate the switch from latent to lytic replication in EBV-infected cells. DNA viruses often modulate the function of critical cell cycle proteins to maximize the efficiency of virus replication. Here we have examined the effect of BRLF1 on cell cycle progression. A replication-deficient adenovirus expressing BRLF1 (AdBRLF1) was used to infect normal human fibroblasts and various epithelial cell lines. BRLF1 expression induced S phase entry in contact-inhibited fibroblasts and in the human osteosarcoma cell line U-2 OS. AdBRLF1 infection produced a dramatic increase in the level of E2F1 but not E2F4. In contrast, the levels of Rb, p107, and p130 were decreased in AdBRLF1-infected cells. Electrophoretic mobility shift assays confirmed an increased level of free E2F1 in the AdBRLF1-infected human fibroblasts. Consistent with the previously described effect of E2F1, AdBRLF1-infected fibroblasts had increased levels of p53 and p21 and died by apoptosis. BRLF1-induced activation of E2F1 may be required for efficient EBV lytic replication, since at least one critical viral replication gene (the viral DNA polymerase) is activated by E2F (C. Liu, N. D. Sista, and J. S. Pagano, J. Virol. 70:2545–2555, 1996).
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18

Chiu, Ya-Fang, Chao-Ping Tung, Yu-Hisu Lee, Wen-Hung Wang, Ching Li, Jia-Yan Hung, Chen-Yu Wang, Yasushi Kawaguchi, and Shih-Tung Liu. "A comprehensive library of mutations of Epstein–Barr virus." Journal of General Virology 88, no. 9 (September 1, 2007): 2463–72. http://dx.doi.org/10.1099/vir.0.82881-0.

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A mutant library of 249 mutants with mutations that span the entire Epstein–Barr virus (EBV) genome was generated by transposition with EZ : : TN <KAN-2> and insertion with an apramycin resistance gene by a PCR-targeting method. This study also demonstrates the feasibility of generating deletions and site-specific mutations in the BRLF1 promoter on the EBV genome to determine the regions in the promoter that are crucial to transcription. Analysing BZLF1 and BRLF1 mutants by microarray analysis revealed that these two genes regulate the transcription of EBV lytic genes differently. A BZLF1 mutation affects global expression of EBV lytic genes; almost no lytic gene is expressed by the mutant after lytic induction. However, although a BRLF1 mutant still transcribes most lytic genes, the expression of these lytic genes is inefficient. Furthermore, this study shows that the proximal Zta-response element in the BRLF1 promoter is crucial to BRLF1 transcription from the EBV genome, despite the fact that another work demonstrated that this site was unimportant in transient transfection analysis. Furthermore, mutants with a mutation in BDLF1 and BORF1 cannot assemble viral capsids. Results of this study demonstrate the usefulness of a comprehensive mutant library in genetic analyses of EBV.
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19

Chang, Pey-Jium, Yu-Sun Chang, and Shih-Tung Liu. "Role of Rta in the Translation of Bicistronic BZLF1 of Epstein-Barr Virus." Journal of Virology 72, no. 6 (June 1, 1998): 5128–36. http://dx.doi.org/10.1128/jvi.72.6.5128-5136.1998.

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ABSTRACT The BZLF1 gene of Epstein-Barr virus (EBV), which encodes a transcription factor, Zta, is transcribed into monocistronic and bicistronic mRNAs from two different promoters during the immediate-early stage of the EBV lytic cycle. It is generally accepted that the Zta protein translated from the monocistronic mRNA profoundly influences the activation of the EBV lytic cycle. In this study, we constructed a plasmid, pCMV-RZLUC, which can transcribe a bicistronic mRNA consisting of BRLF1 and a BZLF1-luc fusion gene under latent conditions. P3HR1 cells transfected with this plasmid produce a luciferase activity which is approximately 17-fold higher than the activity exhibited by pRZLUC, a plasmid incapable of transcribing the bicistronic mRNA. Genetic analyses indicated that mutations in BRLF1 not only can decrease the translation of the fusion gene from the bicistronic mRNA but can also be complemented by a functional BRLF1 gene in cis. This observation implies that the product of BRLF1, Rta, is involved in the translation of the downstream gene. Results presented herein also demonstrate that these mutations cannot be complemented in trans with a plasmid overexpressing Rta, suggesting that the amount of Rta in the vicinity of the intercistronic region may be crucial for the translation. Furthermore, our results correspond to those of previous investigations indicating that the Zta protein can be translated from the bicistronic mRNA and that, similar to the translation of bicistronic ZLUC, mutations in BRLF1 also hinder the translation of Zta from the BRLF1-BZLF1 bicistronic mRNA. Translation of Zta from the bicistronic mRNA may play an essential role in the activation of the EBV lytic cycle.
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Saxena, Ashish, Beicong Ma, Laura Schramm, and Nouria Hernandez. "Structure-Function Analysis of the Human TFIIB-Related Factor II Protein Reveals an Essential Role for the C-Terminal Domain in RNA Polymerase III Transcription." Molecular and Cellular Biology 25, no. 21 (November 1, 2005): 9406–18. http://dx.doi.org/10.1128/mcb.25.21.9406-9418.2005.

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ABSTRACT The transcription factors TFIIB, Brf1, and Brf2 share related N-terminal zinc ribbon and core domains. TFIIB bridges RNA polymerase II (Pol II) with the promoter-bound preinitiation complex, whereas Brf1 and Brf2 are involved, as part of activities also containing TBP and Bdp1 and referred to here as Brf1-TFIIIB and Brf2-TFIIIB, in the recruitment of Pol III. Brf1-TFIIIB recruits Pol III to type 1 and 2 promoters and Brf2-TFIIIB to type 3 promoters such as the human U6 promoter. Brf1 and Brf2 both have a C-terminal extension absent in TFIIB, but their C-terminal extensions are unrelated. In yeast Brf1, the C-terminal extension interacts with the TBP/TATA box complex and contributes to the recruitment of Bdp1. Here we have tested truncated Brf2, as well as Brf2/TFIIB chimeric proteins for U6 transcription and for assembly of U6 preinitiation complexes. Our results characterize functions of various human Brf2 domains and reveal that the C-terminal domain is required for efficient association of the protein with U6 promoter-bound TBP and SNAPc, a type 3 promoter-specific transcription factor, and for efficient recruitment of Bdp1. This in turn suggests that the C-terminal extensions in Brf1 and Brf2 are crucial to specific recruitment of Pol III over Pol II.
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Francis, Amy, Tobias Ragoczy, Lyn Gradoville, Lee Heston, Ayman El-Guindy, Yoshimi Endo, and George Miller. "Amino Acid Substitutions Reveal Distinct Functions of Serine 186 of the ZEBRA Protein in Activation of Early Lytic Cycle Genes and Synergy with the Epstein-Barr Virus R Transactivator." Journal of Virology 73, no. 6 (June 1, 1999): 4543–51. http://dx.doi.org/10.1128/jvi.73.6.4543-4551.1999.

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ABSTRACT The ZEBRA protein mediates the switch between the latent and lytic life cycles of Epstein-Barr virus. Z(S186A), a point mutant in ZEBRA’s basic domain in which serine 186 is changed to alanine, is unable to induce expression of lytic cycle mRNAs or proteins from the latent EBV genome even though it retains the ability to activate transcription from reporters bearing known ZEBRA-responsive promoters (A. L. Francis et al., J. Virol. 71:3054–3061, 1997). We now describe three distinct phenotypes of ZEBRA mutants bearing different amino acid substitutions at S186. These phenotypes are based on the capacity of the mutants to activate expression of the BRLF1 and BMRF1 genes, which are targets of ZEBRA’s action, and to synergize with the BRLF1 gene product Rta (R transactivator) in activating expression of downstream genes. One mutant class, represented by Z(S186T), was similar to the wild type, although reduced in the capacity to activate BRLF1 and BMRF1 early lytic cycle genes from the latent virus. A second class, represented by Z(S186C) and Z(S186G), was impaired in transcriptional activation, unable to activate early lytic cycle products from the latent virus, and not rescued by overexpression of Rta. A third class, Z(S186A), although unable by itself to activate BRLF1 or other lytic cycle genes, synergized with Rta. Rta rescued the capacity of Z(S186A) to activate the BMRF1 early lytic cycle gene from the latent virus. All mutant classes bound to DNA in vitro, although their capacity to bind to different ZEBRA response elements varied. Serine 186 of ZEBRA is a critical residue that is required for the distinct activities of induction of BRLF1 expression and for synergy with Rta. Since only Z(S186T) among the mutants behaved similarly to the wild type, activation of BRLF1 likely requires phosphorylation of S186. However, since Z(S186A) could synergize with Rta, synergy with Rta does not appear to be dependent on phosphorylation of S186. S186 likely mediates DNA recognition on the BRLF1 promoter in the context of the latent virus, protein-protein interactions, or both. The Z(S186) mutants define the amino acid side chains required for these functions.
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Lin, Mingen, Chenghao Huang, Wenfeng Ren, Jun Chen, Ningshao Xia, and Shuping Zhong. "Mitogen- and Stress-Activated Protein Kinase 1 Mediates Alcohol-Upregulated Transcription of Brf1 and tRNA Genes to Cause Phenotypic Alteration." Oxidative Medicine and Cellular Longevity 2020 (June 27, 2020): 1–13. http://dx.doi.org/10.1155/2020/2067959.

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Upregulation of Brf1 (TFIIB-related factor 1) and Pol III gene (RNA polymerase III-dependent gene, such as tRNAs and 5S rRNA) activities is associated with cell transformation and tumor development. Alcohol intake causes liver injury, such as steatosis, inflammation, fibrosis, and cirrhosis, which enhances the risk of HCC development. However, the mechanism of alcohol-promoted HCC remains to be explored. We have designed the complementary research system, which is composed of cell lines, an animal model, human samples, and experiments in vivo and in vitro, to carry out this project by using molecular biological, biochemical, and cellular biological approaches. It is a unique system to explore the mechanism of alcohol-associated HCC. Our results indicate that alcohol upregulates Brf1 and Pol III gene (tRNAs and 5S rRNA) transcription in primary mouse hepatocytes, immortalized mouse hepatocyte-AML-12 cells, and engineered human HepG2-ADH cells. Alcohol activates MSK1 to upregulate expression of Brf1 and Pol III genes, while inhibiting MSK1 reduces transcription of Brf1 and Pol III genes in alcohol-treated cells. The inhibitor of MSK1, SB-747651A, decreases the rates of cell proliferation and colony formation. Alcohol feeding promotes liver tumor development of the mouse. These results, for the first time, show the identification of the alcohol-response promoter fragment of the Pol III gene key transcription factor, Brf1. Our studies demonstrate that Brf1 expression is elevated in HCC tumor tissues of mice and humans. Alcohol increases cellular levels of Brf1, resulting in enhancement of Pol III gene transcription in hepatocytes through MSK1. Our mechanism analysis has demonstrated that alcohol-caused high-response fragment of the Brf1 promoter is at p-382/+109bp. The MSK1 inhibitor SB-747651A is an effective reagent to repress alcohol-induced cell proliferation and colony formation, which is a potential pharmaceutical agent. Developing this inhibitor as a therapeutic approach will benefit alcohol-associated HCC patients.
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Loveridge, Carolyn J., Sarah Slater, Kirsteen J. Campbell, Noor A. Nam, John Knight, Imran Ahmad, Ann Hedley, et al. "BRF1 accelerates prostate tumourigenesis and perturbs immune infiltration." Oncogene 39, no. 8 (November 18, 2019): 1797–806. http://dx.doi.org/10.1038/s41388-019-1106-x.

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AbstractBRF1 is a rate-limiting factor for RNA Polymerase III-mediated transcription and is elevated in numerous cancers. Here, we report that elevated levels of BRF1 associate with poor prognosis in human prostate cancer. In vitro studies in human prostate cancer cell lines demonstrated that transient overexpression of BRF1 increased cell proliferation whereas the transient downregulation of BRF1 reduced proliferation and mediated cell cycle arrest. Consistent with our clinical observations, BRF1 overexpression in a Pten-deficient mouse (PtenΔ/ΔBRF1Tg) prostate cancer model accelerated prostate carcinogenesis and shortened survival. In PtenΔ/ΔBRF1Tg tumours, immune and inflammatory processes were altered, with reduced tumoral infiltration of neutrophils and CD4 positive T cells, which can be explained by decreased levels of complement factor D (CFD) and C7 components of the complement cascade, an innate immune pathway that influences the adaptive immune response. We tested if the secretome was involved in BRF1-driven tumorigenesis. Unbiased proteomic analysis on BRF1-overexpresing PC3 cells confirmed reduced levels of CFD in the secretome, implicating the complement system in prostate carcinogenesis. We further identify that expression of C7 significantly correlates with expression of CD4 and has the potential to alter clinical outcome in human prostate cancer, where low levels of C7 associate with poorer prognosis.
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Benjamin, Don, Martin Schmidlin, Lu Min, Brigitte Gross, and Christoph Moroni. "BRF1 Protein Turnover and mRNA Decay Activity Are Regulated by Protein Kinase B at the Same Phosphorylation Sites." Molecular and Cellular Biology 26, no. 24 (October 9, 2006): 9497–507. http://dx.doi.org/10.1128/mcb.01099-06.

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ABSTRACT BRF1 posttranscriptionally regulates mRNA levels by targeting ARE-bearing transcripts to the decay machinery. We previously showed that protein kinase B (PKB) phosphorylates BRF1 at Ser92, resulting in binding to 14-3-3 and impairment of mRNA decay activity. Here we identify an additional regulatory site at Ser203 that cooperates in vivo with Ser92. In vitro kinase labeling and wortmannin sensitivity indicate that Ser203 phosphorylation is also performed by PKB. Mutation of both serines to alanine uncouples BRF1 from PKB regulation, leading to constitutive mRNA decay even in the presence of stabilizing signals. BRF1 protein is labile because of proteasomal degradation (half-life, <3 h) but becomes stabilized upon phosphorylation and is less stable in PKBα−/− cells. Surprisingly, phosphorylation-dependent protein stability is also regulated by Ser92 and Ser203, with parallel phosphorylation required at these sites. Phosphorylation-dependent binding to 14-3-3 is abolished only when both sites are mutated. Cell compartment fractionation experiments support a model in which binding to 14-3-3 sequesters BRF1 through relocalization and prevents it from executing its mRNA decay activity, as well as from proteasomal degradation, thereby maintaining high BRF1 protein levels that are required to reinstate decay upon dissipation of the stabilizing signal.
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Zhang, Huamin, Junqing Wu, Zihui Dai, Meiling Qin, Lingyu Hao, Yanjing Ren, Qingfei Li, and Lugang Zhang. "Allelism analysis of BrRfp locus in different restorer lines and map-based cloning of a fertility restorer gene, BrRfp1, for pol CMS in Chinese cabbage (Brassica rapa L.)." Theoretical and Applied Genetics 130, no. 3 (November 28, 2016): 539–47. http://dx.doi.org/10.1007/s00122-016-2833-9.

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26

Ye, Jianjiang, Lyndle Gradoville, and George Miller. "Cellular Immediate-Early Gene Expression Occurs Kinetically Upstream of Epstein-Barr Virus bzlf1 and brlf1 following Cross-Linking of the B Cell Antigen Receptor in the Akata Burkitt Lymphoma Cell Line." Journal of Virology 84, no. 23 (September 22, 2010): 12405–18. http://dx.doi.org/10.1128/jvi.01415-10.

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ABSTRACT The Epstein-Barr virus (EBV) lytic activator genes bzlf1 and brlf1 are conventionally referred to as immediate-early (IE) genes. However, previous studies showed that the earliest expression of these genes was blocked by cycloheximide when the EBV lytic cycle was induced by histone deacetylase (HDAC) inhibitors and protein kinase C agonists. Anti-IgG activates a complex signal transduction pathway that leads to EBV lytic activation in the Akata cell line. Here we demonstrate that in Akata cells, where lytic cycle activation occurs very rapidly after anti-IgG treatment, de novo protein synthesis is also required for induction of bzlf1 and brlf1 expression. New protein synthesis is required up to 1.25 h after application of anti-IgG; bzlf1 and brlf1 mRNAs can be detected 1.5 h after anti-IgG. Five cellular IE genes were shown to be expressed by 1 h after addition of anti-IgG, and their expression preceded that of bzlf1 and brlf1. These include early growth response genes (egr1, egr2, and egr3) and nuclear orphan receptors (nr4a1 and nr4a3). These genes were activated by anti-IgG treatment of Akata cells with and without the EBV genome; therefore, their expression was not dependent on expression of any EBV gene product. EGR1, EGR2, and EGR3 proteins were kinetically upstream of ZEBRA and Rta proteins. Expression of EGR1, ZEBRA, and Rta proteins were inhibited by bisindolylmaleimide X, a selective inhibitor of PKC. The findings suggest a revised model in which the signal transduction cascade activated by cross-linking of the B cell receptor induces expression of cellular IE genes, such as early growth response and nuclear orphan receptor genes, whose products, in turn, regulate bzlf1 and brlf1 expression.
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27

Huang, Chenghao, Yanmei Zhang, and Shuping Zhong. "Alcohol Intake and Abnormal Expression of Brf1 in Breast Cancer." Oxidative Medicine and Cellular Longevity 2019 (October 31, 2019): 1–9. http://dx.doi.org/10.1155/2019/4818106.

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Breast cancer is the most common malignant disease of females. Overall, one woman in every nine will get breast cancer at some time in her life. Epidemiological studies have indicated that alcohol consumption has most consistently been associated with breast cancer risk. However, the mechanism of alcohol-associated breast cancer remains to be addressed. Little is known about the effects of alcohol consumption on Brf1 (TFIIIB-related factor 1) expression and RNA Pol III gene (RNA polymerase III-dependent gene) transcription, which are responsible for protein synthesis and tightly linked to cell proliferation, cell transformation, and tumor development. Emerging evidences have indicated that alcohol induces deregulation of Brf1 and Pol III genes to cause the alterations of cell phenotypes and tumor formation. In this paper, we summarize the progresses regarding alcohol-caused increase in the expression of Brf1 and Pol III genes and analysis of its molecular mechanism of breast cancer. As the earlier and accurate diagnosis approach of breast cancer is not available yet, exploring the molecular mechanism and identifying the biomarker of alcohol-associated breast cancer are especially important. Recent studies have demonstrated that Brf1 is overexpressed in most ER+ (estrogen receptor positive) cases of breast cancer and the change in cellular levels of Brf1 reflects the therapeutic efficacy and prognosis of this disease. It suggests that Brf1 may be a potential diagnosis biomarker and a therapeutic target of alcohol-associated breast cancer.
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Dumay-Odelot, Hélène, Joël Acker, Rosalia Arrebola, André Sentenac, and Christian Marck. "Multiple Roles of the τ131 Subunit of Yeast Transcription Factor IIIC (TFIIIC) in TFIIIB Assembly." Molecular and Cellular Biology 22, no. 1 (January 1, 2002): 298–308. http://dx.doi.org/10.1128/mcb.22.1.298-308.2002.

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ABSTRACT Yeast transcription factor IIIC (TFIIIC) plays a key role in assembling the transcription initiation factor TFIIIB on class III genes after TFIIIC-DNA binding. The second largest subunit of TFIIIC, τ131, is thought to initiate TFIIIB assembly by interacting with Brf1/TFIIIB70. In this work, we have analyzed a TFIIIC mutant (τ131-ΔTPR2) harboring a deletion in τ131 removing the second of its 11 tetratricopeptide repeats. Remarkably, this thermosensitive mutation was selectively suppressed in vivo by overexpression of B”/TFIIIB90, but not Brf1 or TATA-binding protein. In vitro, the mutant factor preincubated at restrictive temperature bound DNA efficiently but lost transcription factor activity. The in vitro transcription defect was abolished at high concentrations of B” but not Brf1. Copurification experiments of baculovirus-expressed proteins confirmed a direct physical interaction between τ131 and B”. τ131, therefore, appears to be involved in the recruitment of both Brf1 and B”.
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Moir, Robyn D., Karen V. Puglia, and Ian M. Willis. "A Gain-of-Function Mutation in the Second Tetratricopeptide Repeat of TFIIIC131 Relieves Autoinhibition of Brf1 Binding." Molecular and Cellular Biology 22, no. 17 (September 1, 2002): 6131–41. http://dx.doi.org/10.1128/mcb.22.17.6131-6141.2002.

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ABSTRACT The interaction between the tetratricopeptide repeat (TPR)-containing subunit of TFIIIC, TFIIIC131, and the TFIIB-related factor Brf1 represents a limiting step in the assembly of the RNA polymerase III (pol III) initiation factor TFIIIB. This assembly reaction is facilitated by dominant mutations that map in and around TPR2. Structural modeling of TPR1 to TPR3 from TFIIIC131 shows that one such mutation, PCF1-2, alters a residue in the ligand-binding groove of the TPR superhelix whereas another mutation, PCF1-1, changes a surface-accessible residue on the back side of the TPR superhelix. In this work, we show that the PCF1-1 mutation (H190Y) increases the binding affinity for Brf1, but does not affect the binding affinity for Bdp1, in the TFIIIC-dependent assembly of TFIIIB. Interestingly, binding studies with TFIIIC131 fragments indicate that Brf1 does not interact directly at the site of the PCF1-1 mutation. Rather, the data suggest that the mutation overcomes the previously documented autoinhibition of Brf1 binding. These findings together with the results from site-directed mutagenesis support the hypothesis that gain-of-function mutations at amino acid 190 in TPR2 stabilize an alternative conformation of TFIIIC131 that promotes its interaction with Brf1.
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Ragoczy, Tobias, Lee Heston, and George Miller. "The Epstein-Barr Virus Rta Protein Activates Lytic Cycle Genes and Can Disrupt Latency in B Lymphocytes." Journal of Virology 72, no. 10 (October 1, 1998): 7978–84. http://dx.doi.org/10.1128/jvi.72.10.7978-7984.1998.

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ABSTRACT The transition of Epstein-Barr virus (EBV) from latency into the lytic cycle is associated with the expression of two immediate-early viral genes, BZLF1 and BRLF1. Overexpression of ZEBRA, the product of BZLF1, is sufficient to disrupt latency in B lymphocytes and epithelial cells by stimulating expression of lytic cycle genes, including BRLF1. The BRLF1 product Rta functions as a transcriptional activator in both B lymphocytes and epithelial cells. However, Rta has recently been reported to disrupt latency in an epithelial specific manner (S. Zalani, E. Holley-Guthrie, and S. Kenney, Proc. Natl. Acad. Sci. USA 93:9194–9199, 1996). Here we demonstrate that expression of Rta is also sufficient for disruption of latency in a permissive B-cell line. In HH514-16 cells, transfection of Rta leads to synthesis of ZEBRA, viral DNA replication, and late gene expression. However, Rta by itself is less potent than ZEBRA in the ability to activate most early and late lytic cycle genes. In light of previous work implicating ZEBRA in the activation of Rta, we suggest a cooperative model for EBV entry into the lytic cycle. Expression of either BZLF1 or BRLF1 triggers expression of the other immediate-early factor, and together these activators act individually or in synergy on downstream targets to activate the viral lytic cycle.
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Herkilini, Arin, Pancrasia Maria Hendrati, Nur Signa Aini Gumilas, and Hidayat Sulistyo. "Ekspresi mRNA BRLF1 Virus Epstein-Barr dari Biopsi Jaringan Tumor Formalin-Fixed Paraffin Embedeed sebagai Petanda Biologi Molekul Diagnosis Karsinoma Nasofaring." Biosfera 34, no. 3 (October 13, 2017): 138. http://dx.doi.org/10.20884/1.mib.2017.34.3.508.

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Nasopharyngeal carcinoma (NPC) is a malignant tumor that grows in the nasopharynx with a predilection in the fossa Rosenmuller. Epithelial malignancies are often found in populations of China and Southeast Asia, including Indonesia. The NPC incidence in year 2008 as many as 84,400 cases and 51,600 of these cases resulted in death. A total of 120 new cases per year NPC found in hospitals Prof. dr. Margono Soekarjo (RSMS), Purwokerto. The NPC is difficult to be diagnose caused its primary tumor lies closed to the skull base as well as various structures of vital organs. Therefore, methods that can detect early NPC required for inspection.The etiology of NPC is multifactorial consisting of genetic factors, factors of infection Epstein-Barr Virus (EBV) and environmental factors.EBV has two phases in the cycle of infection that is the phase of lytic and latent phase. BRLF1 has an important function as mediator transition from latent e NPC. The research aimed to analysis mRNA BRLF1 expression as a biomarker of NPC diagnosis by RT-PCR and to determine the positivity of RT-PCR method to detect the expression of mRNA BRLF1. The research design was cross sectional study. Samples were FFPE tumor biopsy of NPC WHO III and the total samples were 22 individu from Department of Pathology Anatomy, Prof. Dr. Margono SoekarjoHospital, Purwokerto with informed consent. The positivity of mRNA BRLF1 from FFPE tumor biopsy of NPC WHO III was in 63.6%indicating a high expression.
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32

Peng, Feixia, Ying Zhou, Juan Wang, Baoqiang Guo, Yun Wei, Huan Deng, Zihui Wu, et al. "The transcription factor Sp1 modulates RNA polymerase III gene transcription by controlling BRF1 and GTF3C2 expression in human cells." Journal of Biological Chemistry 295, no. 14 (March 1, 2020): 4617–30. http://dx.doi.org/10.1074/jbc.ra119.011555.

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Specificity protein 1 (Sp1) is an important transcription factor implicated in numerous cellular processes. However, whether Sp1 is involved in the regulation of RNA polymerase III (Pol III)-directed gene transcription in human cells remains unknown. Here, we first show that filamin A (FLNA) represses Sp1 expression as well as expression of TFIIB-related factor 1 (BRF1) and general transcription factor III C subunit 2 (GTF3C2) in HeLa, 293T, and SaOS2 cell lines stably expressing FLNA-silencing shRNAs. Both BRF1 promoter 4 (BRF1P4) and GTF3C2 promoter 2 (GTF3C2P2) contain putative Sp1-binding sites, suggesting that Sp1 affects Pol III gene transcription by regulating BRF1 and GTF3C2 expression. We demonstrate that Sp1 knockdown inhibits Pol III gene transcription, BRF1 and GTF3C2 expression, and the proliferation of 293T and HeLa cells, whereas Sp1 overexpression enhances these activities. We obtained a comparable result in a cell line in which both FLNA and Sp1 were depleted. These results indicate that Sp1 is involved in the regulation of Pol III gene transcription independently of FLNA expression. Reporter gene assays showed that alteration of Sp1 expression affects BRF1P4 and GTF3C2P2 activation, suggesting that Sp1 modulates Pol III–mediated gene transcription by controlling BRF1 and GTF3C2 gene expression. Further analysis revealed that Sp1 interacts with and thereby promotes the occupancies of TATA box–binding protein, TFIIAα, and p300 at both BRF1P4 and GTF3C2P2. These findings indicate that Sp1 controls Pol III–directed transcription and shed light on how Sp1 regulates cancer cell proliferation.
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Quinlivan, E. Byrd, E. A. Holley-Guthrie, M. Norris, D. Gutsch, S. L. Bachenheimer, and S. C. Kenney. "Direct BRLF1 binding is required for cooperative BZLF1/BRLF1 activation of the Epstein-Barr virus early promoter, BMRF1." Nucleic Acids Research 21, no. 14 (1993): 3340. http://dx.doi.org/10.1093/nar/21.14.3340-a.

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Quinlivan, E. Byrd, Elizabeth Holley-Guthrie, Melanie Norris, David Gutsch, S. L. Bachenheimer, and Shannon C. Kenney. "Direct BRLF1 binding is required for cooperative BZLF1/BRLF1 activation of the Epstein-Barr virus early promoter, BMRF1." Nucleic Acids Research 21, no. 8 (1993): 1999–2007. http://dx.doi.org/10.1093/nar/21.8.1999.

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35

VÉLEZ-RAMÍREZ, D. E., L. E. FLORENCIO-MARTÍNEZ, G. ROMERO-MEZA, S. ROJAS-SÁNCHEZ, R. MORENO-CAMPOS, R. ARROYO, J. ORTEGA-LÓPEZ, R. MANNING-CELA, and S. MARTÍNEZ-CALVILLO. "BRF1, a subunit of RNA polymerase III transcription factor TFIIIB, is essential for cell growth of Trypanosoma brucei." Parasitology 142, no. 13 (September 4, 2015): 1563–73. http://dx.doi.org/10.1017/s0031182015001122.

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SUMMARYRNA polymerase III (Pol III) synthesizes small RNA molecules that are essential for cell viability. Accurate initiation of transcription by Pol III requires general transcription factor TFIIIB, which is composed of three subunits: TFIIB-related factor BRF1, TATA-binding protein and BDP1. Here we report the molecular characterization of BRF1 in Trypanosoma brucei (TbBRF1), a parasitic protozoa that shows distinctive transcription characteristics. In silico analysis allowed the detection in TbBRF1 of the three conserved domains located in the N-terminal region of all BRF1 orthologues, namely a zinc ribbon motif and two cyclin repeats. Homology modelling suggested that, similarly to other BRF1 and TFIIB proteins, the TbBRF1 cyclin repeats show the characteristic structure of five α-helices per repeat, connected by a short random-coiled linker. As expected for a transcription factor, TbBRF1 was localized in the nucleus. Knock-down of TbBRF1 by RNA interference (RNAi) showed that this protein is essential for the viability of procyclic forms of T. brucei, since ablation of TbBRF1 led to growth arrest of the parasites. Nuclear run-on and quantitative real-time PCR analyses demonstrated that transcription of all the Pol III-dependent genes analysed was reduced, at different levels, after RNAi induction.
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36

Brennan, RM, JM Burrows, MJ Bell, L. Bromham, PA Csurhes, A. Lenarczyk, J. Sverndal, J. Klintenstedt, MP Pender, and SR Burrows. "Strains of Epstein-Barr virus infecting multiple sclerosis patients." Multiple Sclerosis Journal 16, no. 6 (March 29, 2010): 643–51. http://dx.doi.org/10.1177/1352458510364537.

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Both epidemiological and experimental studies have indicated that the ubiquitous herpesvirus Epstein—Barr virus (EBV) plays a role in the pathogenesis of multiple sclerosis (MS). Some features of MS epidemiology, such as the decline in risk among migrants from high to low MS prevalence areas, suggest the presence of variant EBV strains that increase MS risk. The objective of this study was to investigate whether genetic variability in EBV is associated with MS. Genes encoding for two EBV antigens (EBNA1 and BRRF2) were sequenced in EBV isolates from 40 MS patients and a similar number of control subjects. These viral antigens were chosen for analysis because they are known to stimulate atypical immune responses in MS. Extensive sequence polymorphism was observed within the EBNA1 and BRRF2 genes in isolates from both MS patients and controls. Interestingly, several single nucleotide polymorphisms within the EBNA1 gene, and one within the BRRF2 gene, were found to occur at marginally different frequencies in EBV strains infecting MS patients versus controls. Although this study does not find a simple causal relationship between EBV strains and the occurrence of MS, the existence of haplotypes that occur at different frequencies in MS patients versus controls may provide an area for future study of the role of EBV strain variation in multiple sclerosis.
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Hu, Hui-Lan, Chih-Chien Wu, Jin-Cheng Lee, and Hung-Ta Chen. "A Region of Bdp1 Necessary for Transcription Initiation That Is Located within the RNA Polymerase III Active Site Cleft." Molecular and Cellular Biology 35, no. 16 (June 8, 2015): 2831–40. http://dx.doi.org/10.1128/mcb.00263-15.

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The RNA polymerase III (Pol III)-specific transcription factor Bdp1 is crucial to Pol III recruitment and promoter opening in transcription initiation, yet structural information is sparse. To examine its protein-binding targets within the preinitiation complex at the residue level, photoreactive amino acids were introduced intoSaccharomyces cerevisiaeBdp1. Mutations within the highly conserved SANT domain cross-linked to the transcription factor IIB (TFIIB)-related transcription factor Brf1, consistent with the findings of previous studies. In addition, we identified an essential N-terminal region that cross-linked with the Pol III catalytic subunit C128 as well as Brf1. Closer examination revealed that this region interacted with the C128 N-terminal region, the N-terminal half of Brf1, and the C-terminal domain of the C37 subunit, together positioning this region within the active site cleft of the preinitiation complex. With our functional data, our analyses identified an essential region of Bdp1 that is positioned within the active site cleft of Pol III and necessary for transcription initiation.
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Zhu, Jian, Chunxian Zhou, and Amedeo Caflisch. "Structure-based discovery of selective BRPF1 bromodomain inhibitors." European Journal of Medicinal Chemistry 155 (July 2018): 337–52. http://dx.doi.org/10.1016/j.ejmech.2018.05.037.

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39

Feng, Ping, Ee Chee Ren, Dingxiang Liu, Soh Ha Chan, and Huaizhong Hu. "Expression of Epstein–Barr virus lytic gene BRLF1 in nasopharyngeal carcinoma: potential use in diagnosis." Journal of General Virology 81, no. 10 (October 1, 2000): 2417–23. http://dx.doi.org/10.1099/0022-1317-81-10-2417.

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Tumour cells of undifferentiated nasopharyngeal carcinoma (NPC) consistently harbour Epstein–Barr virus (EBV) genes. Expression of mRNA transcripts associated with EBV latency has been demonstrated in such cells. However, expression of EBV lytic genes has not been well elucidated, although various lines of evidence have suggested that there is EBV replication in NPC tumour cells. We have studied mRNA expression of representative EBV lytic genes by RT–PCR in nasopharynx biopsies obtained from NPC and control individuals. In both NPC and control biopsies, EBV lytic genes BZLF1, BALF2 and BCLF1 were detected readily. However, BRLF1 was detected in NPC biopsies only. The BRLF1 gene was then cloned and expressed in vitro, and the protein product, Rta, was used as an antigen to detect specific antibodies by immunoprecipitation in plasma samples obtained from NPC patients and healthy controls. IgG antibodies directed against Rta were detected in 44 of 53 NPC plasma samples (83·0%), but only in 1 of 53 control samples (1·9%). Furthermore, the antibody binding regions were found in the C-terminal two-thirds of Rta. This serological result confirms indirectly that BRLF1 is specifically expressed in NPC tumour cells. Rta might play an important role in NPC pathogenesis, considering its multiple functions in EBV replication and cell cycles. Moreover, the detection of IgG antibodies directed against Rta could be developed into a diagnostic parameter for NPC.
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40

Countryman, Jill K., Lyndle Gradoville, and George Miller. "Histone Hyperacetylation Occurs on Promoters of Lytic Cycle Regulatory Genes in Epstein-Barr Virus-Infected Cell Lines Which Are Refractory to Disruption of Latency by Histone Deacetylase Inhibitors." Journal of Virology 82, no. 10 (March 12, 2008): 4706–19. http://dx.doi.org/10.1128/jvi.00116-08.

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ABSTRACT Activation of the Epstein-Barr virus (EBV) lytic cycle is mediated through the combined actions of ZEBRA and Rta, the products of the viral BZLF1 and BRLF1 genes. During latency, these two genes are tightly repressed. Histone deacetylase inhibitors (HDACi) can activate viral lytic gene expression. Therefore, a widely held hypothesis is that Zp and Rp, the promoters for BZLF1 and BRLF1, are repressed by chromatin and that hyperacetylation of histone tails, by allowing the access of positively acting factors, leads to transcription of BZLF1 and BRLF1. To investigate this hypothesis, we used chromatin immunoprecipitation (ChIP) to examine the acetylation and phosphorylation states of histones H3 and H4 on Zp and Rp in three cell lines, Raji, B95-8, and HH514-16, which differ in their response to EBV lytic induction by HDACi. We studied the effects of three HDACi, sodium butyrate (NaB), trichostatin A (TSA), and valproic acid (VPA). We also examined the effects of tetradecanoyl phorbol acetate (TPA) and 5-aza-2′-deoxycytidine, a DNA methyltransferase inhibitor, on histone modification. In Raji cells, TPA and NaB act synergistically to activate the EBV lytic cycle and promote an increase in histone H3 and H4 acetylation and phosphorylation at Zp and Rp. Surprisingly, however, when Raji cells were treated with NaB or TSA, neither of which is sufficient to activate the lytic cycle, an increase of comparable magnitude of hyperacetylated and phosphorylated histone H3 at Zp and Rp was observed. In B95-8 cells, NaB inhibited lytic induction by TPA, yet NaB promoted hyperacetylation of H3 and H4. In HH514-16 cells, NaB and TSA strongly activated the EBV lytic cycle and caused hyperacetylation of histone H3 on Zp and Rp. However, when HH514-16 cells were treated with VPA, lytic cycle mRNAs or proteins were not induced, although histone H3 was hyperacetylated as measured by immunoblotting or by ChIP on Zp and Rp. Taken together, our data suggest that open chromatin at EBV BZLF1 and BRLF1 promoters is not sufficient to activate EBV lytic cycle gene expression.
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41

Countryman, Jill, Lyndle Gradoville, Sumita Bhaduri-McIntosh, Jianjiang Ye, Lee Heston, Sarah Himmelfarb, Duane Shedd, and George Miller. "Stimulus Duration and Response Time Independently Influence the Kinetics of Lytic Cycle Reactivation of Epstein-Barr Virus." Journal of Virology 83, no. 20 (August 5, 2009): 10694–709. http://dx.doi.org/10.1128/jvi.01172-09.

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ABSTRACT Epstein-Barr virus (EBV) can be reactivated from latency into the lytic cycle by many stimuli believed to operate by different mechanisms. Cell lines containing EBV differ in their responses to inducing stimuli, yet all stimuli require de novo protein synthesis (44). A crucial step preliminary to identifying these proteins and determining when they are required is to measure the duration of stimulus and response time needed for activation of expression of EBV BRLF1 and BZLF1, the earliest viral indicators of reactivation. Here we show, with four EBV-containing cell lines that respond to different inducing agents, that stimuli that are effective at reactivating EBV can be divided into two main groups. The histone deacetylase inhibitors sodium butyrate and trichostatin A require a relatively long period of exposure, from 2 to 4 h or longer. Phorbol esters, anti-immunoglobulin G (anti-IgG), and, surprisingly, 5-aza-2′-deoxycytidine require short exposures of 15 min or less. The cell/virus background influences the response time. Expression of the EBV BZLF1 and BRLF1 genes can be detected before 2 h in Akata cells treated with anti-IgG, but both long- and short-duration stimuli required 4 or more hr to activate BZLF1 and BRLF1 expression in HH514-16, Raji, or B95-8 cells. Thus, stimulus duration and response time are independent variables. Neither stimulus duration nor response time can be predicted by the number of cells activated into the lytic cycle. These experiments shed new light on the earliest events leading to lytic cycle reactivation of EBV.
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42

Li, Yuling, Nupam P. Mahajan, Jennifer Webster-Cyriaque, Prasanna Bhende, Gregory K. Hong, H. Shelton Earp, and Shannon Kenney. "The C-Mer Gene Is Induced by Epstein-Barr Virus Immediate-Early Protein BRLF1." Journal of Virology 78, no. 21 (November 1, 2004): 11778–85. http://dx.doi.org/10.1128/jvi.78.21.11778-11785.2004.

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ABSTRACT BRLF1 (R) is one of two Epstein-Barr virus (EBV) immediate-early proteins that mediate the switch from the latent to the lytic form of viral replication. In this report, we show that R induces expression of the cellular C-mer gene in a variety of cell lines. C-mer expression was detected in lymphoblastoid cells immortalized with wild-type EBV but not in lymphoblastoid cells immortalized with an EBV that had BRLF1 deleted. Oral hairy leukoplakia tongue tissue, which contains the lytic form of EBV replication, also has enhanced C-mer expression. C-mer is a receptor tyrosine kinase activated by the ligand Gas6. C-mer is required for phagocytosis of apoptotic debris by monocytes/macrophages and retinal pigment epithelial cells and is capable of producing an antiapoptotic signal. Modulation of the C-mer signal transduction cascade by a variety of different approaches did not alter the ability of R to induce lytic EBV gene transcription. Therefore, C-mer activation may be important for some other aspect of lytic EBV infection.
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43

Bamborough, Paul, Heather A. Barnett, Isabelle Becher, Mark J. Bird, Chun-wa Chung, Peter D. Craggs, Emmanuel H. Demont, et al. "GSK6853, a Chemical Probe for Inhibition of the BRPF1 Bromodomain." ACS Medicinal Chemistry Letters 7, no. 6 (May 30, 2016): 552–57. http://dx.doi.org/10.1021/acsmedchemlett.6b00092.

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44

You, Linya, Lin Li, Jinfeng Zou, Kezhi Yan, Jad Belle, Anastasia Nijnik, Edwin Wang, and Xiang-Jiao Yang. "BRPF1 is essential for development of fetal hematopoietic stem cells." Journal of Clinical Investigation 126, no. 9 (August 8, 2016): 3247–62. http://dx.doi.org/10.1172/jci80711.

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45

You, Linya, Jinfeng Zou, Hong Zhao, Nicholas R. Bertos, Morag Park, Edwin Wang, and Xiang-Jiao Yang. "Deficiency of the Chromatin Regulator Brpf1 Causes Abnormal Brain Development." Journal of Biological Chemistry 290, no. 11 (January 7, 2015): 7114–29. http://dx.doi.org/10.1074/jbc.m114.635250.

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46

You, Linya, Kezhi Yan, Jinfeng Zou, Hong Zhao, Nicholas R. Bertos, Morag Park, Edwin Wang, and Xiang-Jiao Yang. "The Chromatin Regulator Brpf1 Regulates Embryo Development and Cell Proliferation." Journal of Biological Chemistry 290, no. 18 (March 15, 2015): 11349–64. http://dx.doi.org/10.1074/jbc.m115.643189.

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47

Cheng, L. H. C., F. H. C. Tsang, L. Wei, C. T. Law, I. O. L. Ng, and C. M. Wong. "The pathological and functional roles of BRPF1 in hepatocellular carcinoma." Annals of Oncology 30 (October 2019): v808. http://dx.doi.org/10.1093/annonc/mdz269.036.

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48

Cabello, Olga A., Antonio Baldini, Manzoor Bhat, Hugo Bellen, and John W. Belmont. "Localization of BRRN1, the Human Homologue ofDrosophila barr,to 2q11.2." Genomics 46, no. 2 (December 1997): 311–13. http://dx.doi.org/10.1006/geno.1997.5021.

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49

Aiello, Giuseppe, Claudio Ballabio, Riccardo Ruggeri, Luca Fagnocchi, Marica Anderle, Ilaria Morassut, Davide Caron, et al. "Truncated BRPF1 Cooperates with Smoothened to Promote Adult Shh Medulloblastoma." Cell Reports 29, no. 12 (December 2019): 4036–52. http://dx.doi.org/10.1016/j.celrep.2019.11.046.

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50

Obi, Juliet O., Mulu Y. Lubula, Gabriel Cornilescu, Amy Henrickson, Kara McGuire, Chiara M. Evans, Margaret Phillips, et al. "The BRPF1 bromodomain is a molecular reader of di-acetyllysine." Current Research in Structural Biology 2 (2020): 104–15. http://dx.doi.org/10.1016/j.crstbi.2020.05.001.

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