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Journal articles on the topic "OTX proteins"
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Klein, William H., and Xiaotao Li. "Function and Evolution of Otx Proteins." Biochemical and Biophysical Research Communications 258, no. 2 (May 1999): 229–33. http://dx.doi.org/10.1006/bbrc.1999.0449.
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Klein, William H., and Xiaotao Li. "Function and Evolution of Otx Proteins." Biochemical and Biophysical Research Communications 260, no. 2 (July 1999): 575. http://dx.doi.org/10.1006/bbrc.1999.0938.
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Acampora, D., V. Avantaggiato, F. Tuorto, and A. Simeone. "Genetic control of brain morphogenesis through Otx gene dosage requirement." Development 124, no. 18 (September 15, 1997): 3639–50. http://dx.doi.org/10.1242/dev.124.18.3639.
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Understanding the genetic mechanisms that control patterning of the vertebrate brain represents a major challenge for developmental neurobiology. Previous data suggest that Otx1 and Otx2, two murine homologs of the Drosophila orthodenticle (otd) gene, might both contribute to brain morphogenesis. To gain insight into this possibility, the level of OTX proteins was modified by altering in vivo the Otx gene dosage. Here we report that Otx genes may cooperate in brain morphogenesis and that a minimal level of OTX proteins, corresponding either to one copy each of Otx1 and Otx2, or to only two copies of Otx2, is required for proper regionalization and subsequent patterning of the developing brain. Thus, as revealed by anatomical and molecular analyses, only Otx1−/−; Otx2+/− embryos lacked mesencephalon, pretectal area, dorsal thalamus and showed an heavy reduction of the Ammon's horn, while the metencephalon was dramatically enlarged occupying the mesencencephalic area. In 8.5 days post coitum (d.p.c.) Otx1−/−; Otx2+/− embryos, the expression patterns of mesencephalic-metencephalic (mes-met) markers such as En-1 and Wnt-1 confirmed the early presence of the area fated to give rise to mesencephalon and metencephalon while Fgf-8 transcripts were improperly localized in a broader domain. Thus, in Otx1−/−; Otx2+/− embryos, Fgf-8 misexpression is likely to be the consequence of a reduced level of specification between mes-met primitive neuroepithelia that triggers the following repatterning involving the transformation of mesencephalon into metencephalon, the establishment of an isthmic-like structure in the caudal diencephalon and, by 12.5 d.p.c., the telencephalic expression of Wnt-1 and En-2. Taken together these findings support the existence of a molecular mechanism depending on a precise threshold of OTX proteins that is required to specify early regional diversity between adjacent mes-met territories and, in turn, to allow the correct positioning of the isthmic organizer.
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Kemper, Ryan M., Manfred Meng, and Daniel J. Crona. "Abstract B030: Combined inhibition of BET proteins and PARP promotes impaired DNA damage repair response and cell cycle dysregulation in preclinical models of bladder cancer." Cancer Research 82, no. 23_Supplement_2 (December 1, 2022): B030. http://dx.doi.org/10.1158/1538-7445.cancepi22-b030.
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Abstract Background: Bladder cancer (BC) remains a common and deadly malignancy, with a projected 81,180 new diagnoses and 17,100 deaths in the United States in 2022. According to the MSK/TCGA Bladder Cancer dataset, mutations in DNA damage response (DDR) genes that are part of the homologous recombination (HR) pathway occurred in up to 55% of patients, representing a potential therapeutic target in BC. In previous work, we used UNC’s EpiG Diamond compound library to show that, as a class, inhibition of the methyl-lysine reader bromodomain and extra-terminal domain (BET) proteins potently abrogate BC cell line viability. Here, we evaluated mechanisms related to HR inhibition that could explain pan-BET inhibitor OTX-015’s potency in BC. Methods: 5637 and J82 BC cells were treated with 1 µM OTX-015 or 0.1% DMSO control for 48-hours, total RNA was extracted, and then bulk RNA-sequencing (RNA-seq) was performed on an Illumina NovaSeq 6000 (Novogene, Sacramento, CA). Expression data was analyzed using Geneious Prime v2022.2.1 (Biomatters, San Diego, CA). Cells were then treated with 1 μM OTX-015, 5 μM of the PARP inhibitor olaparib, or combination for gene and protein expression analysis. Gene expression changes in BRCA1, BRCA2, PALB2, and RAD51, as well as MYC as a positive control, were confirmed by RT-PCR in biological triplicates after 48-hour incubation, normalized to an SDHA housekeeper and compared to a 0.1% DMSO control. Western blotting evaluated OTX-015 and olaparib effects on BRCA1, BRCA2, c-MYC, PALB2, and RAD51 protein expression after 72-hour incubation, using a GAPDH loading control and compared to a 0.1% DMSO control. Last, cells were treated with the same treatment schema for 24-72 hours, fixed with methanol, stained with propidium iodide (25 μg/mL), and flow cytometry evaluated effects on cell cycle using a ThermoFisher Attune NxT and FlowJo v10.8.1 (BD Life Sciences, Ashland, OR). Results: Bulk RNA-seq analyses revealed significantly altered expression of HR pathway genes in 5637 and J82 cells treated with OTX-015±olaparib. In 5637 cells, OTX-015 alone significantly reduced BRCA1, BRCA2, PALB2 and RAD51 expression, (n=3; P<0.001 for all), but only PALB2 and RAD51 expression was significantly reduced after combination treatment (n=3; P<0.001 for both). In J82 cells, OTX-015 alone and combination treatment significantly reduced BRCA1, PALB2 and RAD51 expression, (n=3; P<0.001 for all). Similarly, both OTX-015 and combination treatment resulted in reduced BRCA1, c-MYC, PALB2 and RAD51 protein expression in both cell lines. In both cell lines, combination treatment resulted in a substantially increased G2/M fraction at 48 hours compared to 0.1% DMSO (5637 cells: 62.9% vs 12.6% G2/M; J82 cells: 28.2% vs 17.8% G2/M). Conclusions: These data indicate that OTX-015-mediated inhibition of RAD51 and PALB2 could be responsible for impaired HR. Cell cycle data revealed a G2/M stall, rather than an S phase stall, suggesting mechanisms independent from impaired HR could be responsible for cell cycle dysregulation. Citation Format: Ryan M. Kemper, Manfred Meng, Daniel J. Crona. Combined inhibition of BET proteins and PARP promotes impaired DNA damage repair response and cell cycle dysregulation in preclinical models of bladder cancer. [abstract]. In: Proceedings of the AACR Special Conference: Cancer Epigenomics; 2022 Oct 6-8; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2022;82(23 Suppl_2):Abstract nr B030.
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Kemper, Ryan M., Heemaja Mewada, Jeffrey S. Damrauer, Brian Hardy, Stephen F. Frye, Kenneth H. Pearce, Jesse Raab, William Y. Kim, and Daniel James Crona. "Abstract 3267: ARID1A mutated bladder cancer cells are sensitized to BET protein inhibition with OTX-015." Cancer Research 82, no. 12_Supplement (June 15, 2022): 3267. http://dx.doi.org/10.1158/1538-7445.am2022-3267.
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Abstract Background: Bladder cancer (BC) is a common and deadly disease. Inactivating ARID1A mutations occur in up to 30% of metastatic BC tumors, making it the most commonly mutated epigenetic gene and the 4th most commonly mutated gene overall in BC. ARID1A mutations are associated with decreased response to therapy and poor prognosis; thus, there is a need to develop therapies specifically targeting ARID1A mutant tumors. Using the UNC EpiG Diamond compound library, a set of well-annotated small molecule probes targeting chromatin regulatory proteins, we determined that inhibitors of bromodomain and extraterminal (BET) proteins potently inhibit the viability of BC cells. Here, we tested the hypothesis that ARID1Amut cells are particularly sensitized to the pan-BET inhibitor OTX-015. Methods: AR1D1A-competent (ARID1AWT) 5637 and ARID1A-mutated (ARID1Amut) HT1197 cells were treated with eight ascending concentrations of OTX-015 (0.1 nM-100 µM), and cell viability was measured using CellTiter-Glo™ after 72-120-hour incubations. IC50 values were calculated using a four-parameter non-linear regression model. Gene expression of BET inhibitor target genes, MYC, ARID1B, and RAD51, were evaluated by RT-PCR after a 48-hour incubation, normalized to an SDHA housekeeper and compared to a 0.1% DMSO control. CellTiter-Glo™ and RT-PCR experiments were conducted in technical and biologic triplicates. Western blotting evaluated OTX-015 effects on c-MYC, BAF250B (encoded by ARID1B), and RAD51 protein expression after 72-hour incubation. Results: OTX-015 was 8-times more potent in ARID1Amut HT1197 cells at 120 h than in ARID1AWT 5637 cells (IC50: 0.12 μM vs. 1.0 μM). OTX-015 treatment (1 µM) significantly reduced ARID1B and RAD51 mRNA expression versus 0.1% DMSO control (83% and 86% reduction, respectively, both P<0.0001). At the same concentration, OTX-015 did not significantly reduce MYC mRNA expression HT1197 cells (25% reduction, P=0.31), but did significantly reduce MYC expression in 5637 cells (57% reduction, P<0.0001) at 48 h. When comparing HT1197 to 5637 cells, OTX-015 treatment (1 µM) caused a greater reduction in ARID1B mRNA expression (83% vs. 62% reduction, P=0.02) and RAD51 mRNA expression (86% vs. 57%, P=0.001) at 48 h. Finally, OTX-015 treatment (1 µM) also resulted in more dramatically reduced c-MYC, ARID1B and RAD51 protein expression in HT1197 cells at 72 h, when compared to 5637 cells. Conclusions: These preliminary results support future lines of inquiry into the molecular mechanisms that underlie sensitization of ARID1Amut cells to BET protein inhibition. Citation Format: Ryan M. Kemper, Heemaja Mewada, Jeffrey S. Damrauer, Brian Hardy, Stephen F. Frye, Kenneth H. Pearce, Jesse Raab, William Y. Kim, Daniel James Crona. ARID1A mutated bladder cancer cells are sensitized to BET protein inhibition with OTX-015 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3267.
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Acampora, Dario, Massimo Gulisano, and Antonio Simeone. "Genetic and molecular roles of Otx homeodomain proteins in head development." Gene 246, no. 1-2 (April 2000): 23–35. http://dx.doi.org/10.1016/s0378-1119(00)00070-6.
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Senapedis, William, Elmer Figueroa, Kayleigh Gallagher, Jeremiah Farelli, Robert Lyng, Charles O'Donnell, Joseph Newman, and Thomas McCauley. "Abstract 2629: Epigenetic modulation of the MYC oncogene as a potential novel therapy for HCC." Cancer Research 82, no. 12_Supplement (June 15, 2022): 2629. http://dx.doi.org/10.1158/1538-7445.am2022-2629.
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Abstract Hepatocellular carcinoma (HCC), the fourth leading cause of cancer deaths, represents an unmet medical need with few therapeutic options. Sorafenib has been used as a systemic therapy for HCC for >10 years but patients frequently develop resistance with oncogenic c-MYC (MYC) identified as a correlating prognostic factor. MYC over-expression is associated with aggressive disease in up to ~70% of HCC. While MYC represents an attractive therapeutic target, it has historically been considered undruggable, largely because it lacks a structured binding pocket and its expression is tightly autoregulated. The MYC gene and its regulatory elements are part of an insulated genomic domain (IGD), a chromatin looping region anchored by CTCF. Here we describe our approach to specifically modulate levels of MYC expression by utilizing targeted mRNA-encoded proteins, Omega Epigenomic Controllers (OECs), to mediate epigenetic regulation while potentially overcoming MYC autoregulation. For screening, putative OECs were directed to 2 loci on the MYC IGD. Identified target loci were used to design optimized OECs, including development candidate OTX-2002. We characterized OTX-2002 in HCC cell lines, measuring MYC mRNA and cell viability. OTX-2002 was tested for durable epigenetic and transcriptomic changes. Changes in MYC protein levels and pathway signaling were measured using proteomic methods. Finally, we analyzed activity of OTX-2002 in in vivo subcutaneous (subQ) and orthotopic HCC models by assessing tumor volume, tumor-associated bioluminescence (BLI) and immunohistochemistry (IHC). OTX-2002 was effective at decreasing MYC mRNA, protein and cell viability in HCC cells while sparing normal cells. In HCC cells, OTX-2002 median EC50 of inhibition is <0.001 ng/mL for MYC mRNA and 120 ng/mL for cell viability. Importantly, the effects of OTX-2002 persisted for >2 weeks, providing durable MYC mRNA repression. IV delivery of OTX-2002 in lipid nanoparticles at 3 and 6 mg/kg Q5D in a Hep 3B subQ model in athymic nude mice demonstrated statistically significant tumor growth inhibition (TGI) of 54% and 63%, respectively, by Day 23 compared to negative control. OTX-2002-treated mice did not have a significant decrease in bodyweight (BW) compared to negative control or sorafenib-treated mice. IHC of OTX-2002 and control treated tumors showed significant down-regulation of MYC with reduced proliferation (Ki67) and increased apoptosis (Caspase 3). In a Hep 3B orthotopic model 3 mg/kg OTX-2002 Q5D showed a comparable reduction of BLI to sorafenib at 50 mg/kg QD without the reduction in BW. Our findings identify a therapeutic in vitro and in vivo approach that enables transcriptional modulation of the MYC oncogene through precise epigenomic programming of the IGD in which it resides. Targeting MYC in this manner may represent a potentially differentiated and viable approach to the treatment of HCC in humans. Citation Format: William Senapedis, Elmer Figueroa, Kayleigh Gallagher, Jeremiah Farelli, Robert Lyng, Charles O'Donnell, Joseph Newman, Thomas McCauley. Epigenetic modulation of the MYC oncogene as a potential novel therapy for HCC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2629.
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Bellipanni, Gianfranco, Tohru Murakami, O. Geoffrey Doerre, Peter Andermann, and Eric S. Weinberg. "Expression of Otx Homeodomain Proteins Induces Cell Aggregation in Developing Zebrafish Embryos." Developmental Biology 223, no. 2 (July 2000): 339–53. http://dx.doi.org/10.1006/dbio.2000.9771.
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Martin, Richard, Virginie Sanguin-Gendreau, Mathieu Tremblay, Elena Levantini, Christina Magli, and Trang Hoang. "Regulation of SCL Expression by the Homeodomain Protein Otx-1 and the Erythroid Transcription Factor GATA-1." Blood 104, no. 11 (November 16, 2004): 1598. http://dx.doi.org/10.1182/blood.v104.11.1598.1598.
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Abstract Members of the bicoid homeodomain-containing proteins are important in establishing left-right asymmetry and the antero-posterior axis, suggesting that they could also be involved in asymmetric determination within the hematopoietic system. We have previously shown that Otx1, a member of the bicoid homeodomain-containing proteins, is co-expressed with the SCL transcription factor in hematopoietic pluripotent and erythroid progenitor cells and Otx1-deficiency impairs the erythroid compartment in mice, associated with decreased SCL levels. In the present study, we provide molecular and functional evidence that SCL is a direct transcriptional target of Otx1. First, we show by chromatin immunoprecipitation that Otx1 and GATA-1 are specifically bound to the SCL proximal promoter in erythroid cells. Second, Otx-1 synergizes with GATA-1 to activate transcription from the SCL proximal promoter and this activity depends on the integrity of the proximal GATA site of the SCL promoter 1a. At the molecular level, we show that this synergy occurs via a physical interaction between Otx-1 and GATA-1 in erythroid cells, which maps to the homeodomain of Otx-1. Furthermore, a gain of function of Otx1 in primary hematopoietic cells gives rise to a 6-fold increase in endogenous SCL levels, an increase in TER119-positive erythroid cells and a decrease in the number of CD11b-positive myeloid cells. Finally, a gain of function of SCL rescues the erythroid deficiency in Otx1−/− mice, consistent with the view that SCL operates downstream of Otx1. Taken together, our observations indicate that Otx1, GATA-1 and SCL operate within the same genetic pathway to specify the erythroid fate during hematopoiesis.
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Li, Xiaotao, Chin-Kai Chuang, Chai-An Mao, Lynne M. Angerer, and William H. Klein. "Two Otx Proteins Generated from Multiple Transcripts of a Single Gene inStrongylocentrotus purpuratus." Developmental Biology 187, no. 2 (July 1997): 253–66. http://dx.doi.org/10.1006/dbio.1997.8610.
Full textDissertations / Theses on the topic "OTX proteins"
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Onorati, Marco. "Molecular determinants of Xotx2 and Xotx5b action in retinal cell fate specification." Doctoral thesis, Scuola Normale Superiore, 2007. http://hdl.handle.net/11384/85987.
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Cordeiro, Cristianne. "Eggshell Membrane Proteins provide Innate Immune Protection." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/33389.
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The microbiological safety of avian eggs is a major concern for the poultry industry and for consumers due to the potential for severe impacts on public health. Innate immune defense is formed by proteins with antimicrobial and immune-modulatory activities and ensures the protection of the chick embryo against pathogens. The objective of this project was to identify the chicken eggshell membrane (ESM) proteins that play a role in these innate immune defense mechanisms.
We hypothesized that ESM Ovocalyxin-36 (OCX-36) is a pattern recognition protein, and characterized purified ESM OCX-36. OCX-36 has antimicrobial activity against S. aureus and binds E. coli lipopolysaccharide (LPS) and S. aureus lipoteichoic acid (LTA). We additionally investigated the OCX-36 nonsynonymous single nucleotide polymorphisms (SNPs) at cDNA position 211. The corresponding isoforms (proline-71 or serine-71) were purified from eggs collected from genotyped homozygous hens. A significant difference between Pro-71 and Ser-71 OCX-36s for S. aureus LTA binding activity was observed. From these experiments, we confirmed the hypothesis that OCX-36 is a pattern recognition molecule. We also found that OCX-36 has anti-endotoxin properties and is a macrophage immunostimulator to produce NO and TNF-α. Digested OCX-36 down-regulated the expression of genes involved in LPS signaling and inflammatory responses. Moreover, OCX-36-derived peptides inhibited the production of LPS-induced pro-inflammatory mediators associated with endotoxemia in vivo.
Quantitative proteomics analysis of ESMs was performed to evaluate changes in ESM protein abundance during chick embryonic development. Bioinformatics analysis revealed enrichment of proteins associated with antimicrobial and immune protection, vascularization, calcium mobilization and lipid transport, which are vital for chick embryonic development. In unfertilized eggs, protease inhibitors and antimicrobial proteins were enriched.
In summary, the ESMs are enriched in proteins with antimicrobial, antioxidant and immune-modulatory properties, which aid in the development of the chick embryo and protect the embryo and unfertilized egg against pathogen invasion.
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Berhane, Nahom Ahferom. "Antimicrobial Proteins for Human Health." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/37283.
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Bacteria are one of the largest causes of human disease, with millions of deaths every year attributed to bacterial infections, and they have become more difficult to tackle with the widespread emergence of antibiotic resistance. In this thesis, I describe my studies that pursued two approaches: one focus was on using antimicrobial histones as an alternative to treatment for antibiotic resistant bacteria; in another approach the recombinant version of an eggshell cuticle protein was expressed and purified for testing against food-safety pathogens.
One major pathogen that is contributing to this challenge of antibiotic resistance is Staphylococcus aureus. The methicillin-resistant strain of S. aureus leads to increased hospital stays and increased mortality in patients. The impact of such pathogens is worsened when bacteria form surface-attached aggregates known as biofilms. Development of new approaches to eradicate antibiotic- resistant biofilms will benefit human health. This study looked at an alternative method to eradicate bacteria compared to traditional antibiotics. Histones with antimicrobial activity were extracted from chicken blood and tested against methicillin-sensitive and methicillin-resistant strains of Staphylococcus aureus biofilm (MSSA and MRSA). The histone mixture completely eradicated both strains in biofilm form at relatively low concentrations. In addition, the histone mixture also displayed fast kill kinetics against planktonic forms of the two strains. Finally, the interaction of the histone mixture with the bacterial membrane in MRSA biofilms was observed by scanning electron microscopy (SEM). Bacteria treated with the histone mixture showed clear morphological changes, including pore formation and cell collapse. Therefore, the histone mixture purified from chicken red blood cells could prove to be a good alternative to traditional antibiotics for protection against antibiotic-resistant strains of bacteria in their planktonic and biofilm forms.
Reduction of food-borne illness is another important aspect in the promotion of human health. A significant contributor to food-borne illness is contaminated table eggs. The unfertilized egg can be contaminated by a variety of pathogens including Salmonella spp. and Bacillus spp. The egg is protected by the eggshell which is traversed by respiratory pores that are normally covered by a cuticle plug to restrict pathogen entry. This cuticle consists of several proteins including ovocaxlyin-32 (OCX-32). OCX-32 has a large number of naturally occurring haplotypes due non-synonymous single nucleotide polymorphisms (SNPs). In this study, the goal was to express five of the most common haplotypes of OCX-32 in Escherichia coli and purify the recombinant protein for assay of its antimicrobial activity. Five constructs that contain the cDNA of common OCX-32 haplotypes (A, B, C, D, and O) with a histidine tag at the C-terminus were generated. The constructs were subcloned into pGEX4T-1 vector which encodes Glutathione-S-transferase (GST) upstream of the multiple cloning site. My study developed methods to optimize the expression conditions, and to increase the solubility of the recombinant protein. Various expression strains of E. coli and solubility buffers were tested. In addition, the construct was subcloned into a plasmid containing the small ubiquitin-like modifier (SUMO) fusion tag; the solubility of the new SUMO-OCX-32 haplotype A recombinant fusion protein was evaluated. The best results were obtained by slow dialysis refolding of denatured SUMO-OCX-32 fusion protein. This recombinant protein showed almost complete solubility with minimal precipitation and was tested against the egg-related pathogen, Bacillus cereus. Unfortunately, the SUMO-OCX-32 recombinant protein did not inhibit growth of B. cereus.
In my studies reported in this thesis, two very different approaches were taken. A histone mixture was isolated from an abundant starting material, which proved to be highly effective and promising in the eradication of S. aureus biofilms at relatively low concentrations. Alternatively, expression of a soluble recombinant protein for functional activity assay was very challenging and required the optimization of a number of methods to prepare soluble protein for testing. One of the methods tested proved effective in obtaining large amounts of soluble protein. However, further developmental work will be essential to determine if this approach is a viable strategy in acquiring functional protein.
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Oliveira, Moreira Vanessa. "OTX2 homeoprotein and amyloid protein in adult neurogenesis and choroid plexus functions." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS286.
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Le plexus choroïde est une structure fortement vascularisée. Situé dans les ventricules cérébraux, il est responsable de la production du liquide céphalorachidien (LCR) contenant un large panel de molécules essentielles aux diverses fonctions cérébrales. Ma thèse a porté sur la découverte de deux protéines exprimées par le plexus choroïde qui modulent la neurogenèse adulte chez la souris : homéoprotéine OTX2 et la protéine précurseur de l'amyloide (PPA). OTX2 est fortement exprimé dans le plexus choroïde et est sécrété dans le LCR. Nous avons découvert qu'il peut réguler la neurogenèse chez la souris adulte en transférant depuis les cellules du plexus choroïde dans les astrocytes de soutien de la zone sous-ventriculaire (ZSV) et de la chaine migratoire rostral (CMR). Nous avons mis en évidence un mécanisme potentiel par lequel OTX2 modifie l'expression des protéines de la matrice extracellulaire spécifiques des astrocytes, ce qui ralentit la migration des neuroblastes dans la CMR et diminue le nombre de nouveaux neurones dans le bulbe olfactif. De plus, grâce à une analyse transcriptomique du plexus choroïde à partir de modèles de souris knockout conditionnels et constitutifs pour Otx2 chez l'adulte, nous avons montré qu'OTX2 régule l'expression des gènes impliqués dans de nombreuses fonctions homéostatiques. Associé à une approche d’élimination virale d'OTX2, nous avons confirmé son implication dans la réponse immunitaire, la réponse au stress oxydatif, l’épissage et homéostasie des métaux. Ces résultats démontrent qu'OTX2 est un régulateur majeur des fonctions essentielles du plexus choroïde pour le maintien de homéostasie cérébrale. Enfin, la PPA est également fortement exprimée dans le plexus choroïde et son domaine soluble est libéré dans le LCR. Lorsque nous avons réduit les concentrations de PPA dans le plexus choroïde chez la souris adulte, nous avons observé une diminution de la prolifération dans les deux niches neurogéniques : la ZSV et le gyrus denté de l'hippocampe (GD). L'augmentation des concentrations de PPA a entraîné une prolifération accrue dans ces deux niches. Pour mesurer l'impact sur les fonctions cérébrales de la PPA extracellulaire provenant du plexus choroïde, nous avons exprimé spécifiquement dans le plexus choroïde de souris sauvage adultes, la PPA humaine porteuse de mutations SwInd de la maladie d'Alzheimer familiale. Après 6 mois, la prolifération dans la ZSV et le GD a été considérablement réduite. Après 12 mois, des souris ont montré des déficits d'apprentissage inverse dans des expériences de comportement en champ ouvert et ont montré une plasticité altérée dans la potentialisation à long terme (PLT) mesurée par stimulation à haute fréquence de tranches d'hippocampeThe choroid plexus is a richly vascularized structure located in brain ventricles and is responsible for the production of cerebrospinal fluid (CSF) containing a large panel of molecules essential for various brain functions. My thesis focused on the discovery of two proteins expressed by the choroid plexus that modulate adult neurogenesis in mice: the OTX2 homeoprotein transcription factor and the amyloid precursor protein (APP). OTX2 is highly expressed in the choroid plexus and is secreted into the CSF. We found that it can regulate neurogenesis in the adult mouse by transferring into supporting astrocytes of the subventricular zone (SVZ) and rostral migratory stream (RMS). We revealed a potential mechanism whereby OTX2 alters the expression of astrocyte-specific extracellular matrix proteins, resulting in slowed neuroblast migration in RMS and decreased newborn neurons in the olfactory bulb. Moreover, by transcriptomic analysis of the choroid plexus from conditional and constitutive Otx2 knockdown adult mouse models, we shown that OTX2 regulates the expression of genes implicated in numerous homeostatic functions. Coupled with a viral Otx2 knockdown approach, we confirmed its involvement in immune response, oxidative stress response, splicing and metal homeostasis. These findings provide evidence that OTX2 is a major regulator of essential choroid plexus functions for the maintenance of brain homeostasis. Finally, APP is also highly expressed in the choroid plexus and its soluble domain is released into the CSF. When we reduced APP levels in the adult mouse choroid plexus, we observed decreased proliferation in both neurogenic niches: SVZ and hippocampus dentate gyrus (DG). Increasing APP levels resulted in increased proliferation in both niches. To gage the impact on brain function of extracellular APP coming from choroid plexus, we expressed, specifically in choroid plexus of adult wild type mice, the human APP bearing SwInd mutations of familial Alzheimer disease. After 6 months, proliferation in SVZ and DG were significantly reduced. After 12 months, mice showed reversal learning deficits in open field behavior experiments and showed impaired plasticity in long term potentiation (LTP) measured by high frequency stimulation of hippocampus slices
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Wu, Fei. "Novel octaheme cytochrome c tetrathionate reductase (OTR) from Shewanella oneidensis MR-1." Thesis, University of Edinburgh, 2010. http://hdl.handle.net/1842/4725.
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Octa-heme cytochrome c tetrathionate reductase (OTR) from Shewanella oneidensis MR-1 is a periplasmic protein and shows several extraordinary structural features around its active-site heme. OTR has been found able to catalyse the in vitro reduction of tetrathionate, nitrite, hydroxylamine and hydrogen peroxide. However the physiological function of this novel protein remains unknown. The subject of this thesis is the in vitro catalytic mechanism and the in vivo function of OTR. As OTR displays great similarity with bacterial penta-heme cytochrome c nitrite reductase (NrfA) in several aspects, it has been proposed that OTR might be physiologically involved in the metabolism of nitrite or other nitrogenous compounds. However kinetics assays and phenotypes studies carried out in this project suggest this is not the case. In vitro kinetic assays of the reduction of nitrite and hydroxylamine catalysed by OTR showed no significant difference in enzyme activities among the wild-type OTR and its mutant forms which have one active site residue replaced by alanine, namely OTR K153A, C64A, N61A and D150A. And the nitrite reductase activity of OTR (kcat/Km = 1.0×105 M-1•s-1) are much lower than that of NrfA (kcat/Km = ~108 M-1•s-1). These results indicate that OTR is not specifically adapted to reduce nitrite and it cannot compete for nitrite against NrfA in vivo. No phenotype difference was identified between the wild-type and the Δotr strain of Shewanella oneidensis MR-1 when nitrite or nitrate served as the sole electron acceptor. OTR appears not to be involved in the respiration or detoxification of nitrite, which is consistent with previous transcriptional and phenotype reports that involve OTR or its homologues. The in vitro tetrathionate reduction activity of OTR was unable to be reproduced in this project for unknown reasons. Although transcriptomic data from the literature suggest that OTR may be related to the metabolism of sulphur-containing compounds, kinetic and phenotype studies reveal that OTR does not directly participate in the respiration of thiosulfate, sulfite, tetrathionate, polysulfide or elemental sulphur. Cysteine 64 is a highly-conserved amino acid residue of OTR close to the active site and its side-chain sulphur atom is covalently bonded by either an oxygen or a sulphur atom as observed in the crystal structure. Such a modification is potentially important to the function of OTR. ESI mass spectroscopy results show that in native OTR the modified form is around 48 Da heavier than the unmodified form, and the MALDITOF peptide mass spectra show that the modified form could be converted into the unmodified form by reducing agent DTT. These results suggest that the modification could be a cysteine persulfide attaching an extra oxygen atom in the form of water or hydroxide anion.
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Noche, Ramil Romare. "In Vivo Analysis of Zebrafish Exo-rhodopsin Protein and Suprachiasmatic Nucleus Function." Case Western Reserve University School of Graduate Studies / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=case1212772912.
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Konrad, Sebastian [Verfasser], and Thomas [Akademischer Betreuer] Ott. "The plasma membrane attachment of Remorin microdomain marker proteins is stabilized by S-acylation / Sebastian Konrad ; Betreuer: Thomas Ott." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2015. http://d-nb.info/1119706033/34.
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Ott, Dorothee Beatrix [Verfasser], and A. [Akademischer Betreuer] Hartwig. "Einfluss von Aluminium auf die genomische Stabilität und Proteine der Eisenhomöostase / Dorothee Beatrix Ott ; Betreuer: A. Hartwig." Karlsruhe : KIT-Bibliothek, 2019. http://d-nb.info/118734334X/34.
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Ott, Dorothee [Verfasser], and A. [Akademischer Betreuer] Hartwig. "Einfluss von Aluminium auf die genomische Stabilität und Proteine der Eisenhomöostase / Dorothee Beatrix Ott ; Betreuer: A. Hartwig." Karlsruhe : KIT-Bibliothek, 2019. http://d-nb.info/118734334X/34.
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Samuel, Alexander. "Étude génomique des fonctions du facteur de transcription Otx2 dans la rétine de souris adulte." Phd thesis, Université Nice Sophia Antipolis, 2013. http://tel.archives-ouvertes.fr/tel-00933785.
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Pour comprendre comment les gènes du développement exercent de multiples fonctions temporelles, nous prenons comme modèle le facteur de transcription Otx2. Celui-ci est impliqué dans la gastrulation, le développement de l'œil, du système olfactif, de la glande pinéale, du thalamus et de la région cranio-faciale. Dans la rétine adulte, deux tissus distincts expriment Otx2 : l'épithélium pigmenté (RPE) et la rétine neurale, contenant les photorécepteurs. L'ablation globale du gène Otx2 entraîne la dégénérescence exclusive des photorécepteurs alors qu'elle modifie l'expression de gènes surtout dans le RPE. Ces faits suggèrent un mécanisme non autonome, confirmé par des expériences de gain et perte de fonction restreintes au RPE. Pour approcher les fonctions de la protéine Otx2 dans la rétine neurale et le RPE, une étude à grande échelle de ses cibles génomiques a été menée. Les profils distincts d'occupation du génome du RPE et de la rétine neurale suggèrent des fonctions différentes d'Otx2. Dans la rétine neurale, ce profil est très proche de celui du facteur paralogue Crx, indiquant une redondance fonctionnelle entre Otx2 et Crx. Nous avons émis l'hypothèse qu'une combinatoire de partenaires protéiques différents permet de moduler l'action d'Otx2 en sélectionnant des cibles génomiques distinctes. Pour identifier cette combinatoire in vivo et la corréler aux fonctions exercées par Otx2, nous avons créé une lignée de souris exprimant une protéine de fusion Otx2-TAP-tag à un niveau physiologique. Cet outil permettra la purification des complexes protéiques Otx2 in vivo et leur identification par analyse protéomique.
Books on the topic "OTX proteins"
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Kulesh, V. A. Nalogovai͡a︡ advokatura: Ili, kak zashchishchatʹsi͡a︡ ot finansovykh sankt͡s︡iĭ. 2nd ed. Moskva: ZAO Biznes-shkola "Intel-Sintez", 1999.
Find full textBook chapters on the topic "OTX proteins"
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La Rosa, Stefano. "Orthopedia Homeobox Protein (OTP)." In Endocrine Pathology, 588–90. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-62345-6_5195.
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La Rosa, Stefano. "Orthopedia Homeobox Protein (OTP)." In Encyclopedia of Pathology, 1–2. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-319-28845-1_5195-1.
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Guerrieri, N., V. Lavelli, and P. Cerletti. "The Gluten Complex Studied by Urea Denaturation and Red-ox Titration." In Plant Proteins from European Crops, 243–47. Berlin, Heidelberg: Springer Berlin Heidelberg, 1998. http://dx.doi.org/10.1007/978-3-662-03720-1_41.
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Sidhu, Amandeep S., Tharam S. Dillon, and Elizabeth Chang. "Ontological Foundation for Protein Data Models." In On the Move to Meaningful Internet Systems 2005: OTM 2005 Workshops, 916–25. Berlin, Heidelberg: Springer Berlin Heidelberg, 2005. http://dx.doi.org/10.1007/11575863_113.
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Sidhu, Amandeep S., Tharam S. Dillon, and Elizabeth Chang. "Towards Semantic Interoperability of Protein Data Sources." In On the Move to Meaningful Internet Systems 2006: OTM 2006 Workshops, 1835–43. Berlin, Heidelberg: Springer Berlin Heidelberg, 2006. http://dx.doi.org/10.1007/11915072_90.
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Wittekindt, Claus, Elif G�ltekin, Soenke J. Weissenborn, Hans P. Dienes, Herbert J. Pfister, and Jens P. Klussmann. "Expression of p16 Protein Is Associated with Human Papillomavirus Status in Tonsillar Carcinomas and Has Implications on Survival." In Advances in Oto-Rhino-Laryngology, 72–80. Basel: KARGER, 2004. http://dx.doi.org/10.1159/000082474.
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Hoffmann, Christian, and Werner Mäntele. "Optically Transparent Electrodes (Ote) for Spectro- Electrochemical Cells for Investigations on Redox Reactions of Proteins in the UV-, Visible and IR-Region." In Spectroscopy of Biological Molecules: Modern Trends, 595–96. Dordrecht: Springer Netherlands, 1997. http://dx.doi.org/10.1007/978-94-011-5622-6_269.
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"Series Editors." In Protein Carbonylation, b1—b2. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2017. http://dx.doi.org/10.1002/9781119374947.oth.
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"Food Science and Technology Books." In Applied Food Protein Chemistry, 505–6. Chichester, UK: John Wiley & Sons, Ltd, 2015. http://dx.doi.org/10.1002/9781118860588.oth.
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Samson, Willis K. "The Posterior Pituitary and Water Metabolism." In Textbook of Endocrine Physiology. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199744121.003.0009.
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The neurohypophysis, also called the posterior pituitary or neural lobe , is the ventral extension of hypothalamic tissue derived from a developmental down growth of the neuroectoderm forming the floor of the third cerebroventricle. It weighs approximately 0.10–0.15 g in humans and is well developed at birth, having been present since the fifth month of intrauterine life. In addition to containing glial elements called pituicytes, the posterior pituitary is composed of unmyelinated nerve fibers and axon terminals of neurons whose cell bodies reside primarily in the supraoptic and paraventricular hypothalamic nuclei. These hypothalamo-neurohypophyseal fibers deliver the two primary posterior pituitary hormones, oxytocin (OT) and arginine vasopressin (AVP), to the neural lobe in association with specific proteins, the neurophysins, once thought to be carrier proteins but now known to be portions of the OT and AVP precursor molecules. The neurons produce either OT or AVP, and under some circumstances both, and recent studies indicate that in addition to one of these two hormones, other neuropeptides, such as corticotropin-releasing hormone (CRH) and nesfatin-1, and neurotransmitters are also produced in OT- or AVP-containing cells. The phenomenon of colocalization of neuromodulatory agents has aroused a great deal of clinical interest in the role of neuropeptides such as OT and AVP in brain function. Both OT- and AVP-containing nerve fibers, originating in the supraoptic and paraventricular nuclei, project to a variety of other brain structures that are thought to be the sites of their observed central nervous system actions, and to the vicinity of the hypophyseal portal vessels in the median eminence. Release from these fibers of both OT and AVP explains the high levels of these hormones in portal blood and provides the framework for the actions of OT and AVP as modulators of anterior pituitary function. The arterial blood supply of the posterior pituitary is via the inferior (and to some degree the superior) hypophyseal arteries, which originate from the cavernous and postclinoid portions of the internal carotid artery.
Conference papers on the topic "OTX proteins"
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Downing, Benjamin P. B., Astrid van der Horst, Ming Miao, Fred W. Keeley, and Nancy R. Forde. "Probing the Elasticity of Short Proteins with Optical Tweezers." In Optical Trapping Applications. Washington, D.C.: OSA, 2009. http://dx.doi.org/10.1364/ota.2009.otua3.
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Wheaton, Skyler, and Reuven Gordon. "Single Molecule Protein Sizing in Double Nano-hole Optical Tweezers." In Optical Trapping Applications. Washington, D.C.: OSA, 2015. http://dx.doi.org/10.1364/ota.2015.otm3e.5.
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Kargal, Gurunatha, Tim DeWolf, Chad Bartlett, and Reuven Gordon. "Unraveling the dynamics of a single streptavidin protein by optical trapping." In Optical Trapping Applications. Washington, D.C.: OSA, 2017. http://dx.doi.org/10.1364/ota.2017.ottu3e.2.
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Krtolica, Ana, Natacha Le Moan, Philberta Leung, Youngho Seo, Jonathan Winger, Henry Van Brocklin, Michael Kent, and Stephen Cary. "Abstract 2790: Sensitizing the hypoxic tumor microenvironment with OMX, a breakthrough oxygen delivery protein: From protein engineering to clinical trial." In Proceedings: AACR 107th Annual Meeting 2016; April 16-20, 2016; New Orleans, LA. American Association for Cancer Research, 2016. http://dx.doi.org/10.1158/1538-7445.am2016-2790.
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Bartlett, Chad, Gurunatha Kargal, Noa Hacohen, and Reuven Gordon. "Characterization of Heterogeneous Protein Mixtures using Single Molecule Double Nanohole Optical Tweezers." In Optical Trapping Applications. Washington, D.C.: OSA, 2017. http://dx.doi.org/10.1364/ota.2017.ottu3e.1.
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Hsu, Yun Hsiang, and Arnd Pralle. "Thermal Noise Imaging of Cell Membrane Stiffness and Tracking of Membrane Protein Motion." In Optical Trapping Applications. Washington, D.C.: OSA, 2015. http://dx.doi.org/10.1364/ota.2015.ott1d.4.
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Al Balushi, Ahmed A., and Reuven Gordon. "Label-Free Free Solution Single Protein-Small Molecule Binding Kinetics: An Optical Tweezer Approach." In Optical Trapping Applications. Washington, D.C.: OSA, 2015. http://dx.doi.org/10.1364/ota.2015.ott2e.3.
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Moran, Gordon, Amanda Walker, Aline Nixon, David Devadason, Rafeeq Muhammed, Kostas Tsintzas, Sian Kirkham, and Francis Stephens. "OTH-003 Paediatric crohn’s disease patients in remission have a reduced skeletal muscle protein balance after feeding." In British Society of Gastroenterology, Annual General Meeting, 4–7 June 2018, Abstracts. BMJ Publishing Group Ltd and British Society of Gastroenterology, 2018. http://dx.doi.org/10.1136/gutjnl-2018-bsgabstracts.117.
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Yang, Yiming, Andrew J. Sanders, Chunyi Hao, Jiafu Ji, and Wen G. Jiang. "OTU-17 Expression, clinical and prognostic value of dual specific protein phosphatase-7 (DUSP-7) in pancreatic cancer." In Abstracts of the BSG Annual Meeting, 8–12 November 2021. BMJ Publishing Group Ltd and British Society of Gastroenterology, 2021. http://dx.doi.org/10.1136/gutjnl-2021-bsg.23.
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Castellino, F. J., T. Urano, B. Chibber, and Sator V. de Serrano. "ANIONIC INHIBITION OF PLASMINOGEN ACTIVATION." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644374.
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We have found that anions play a significant role in the activation rates of Gluj-plasminogen (GlujPg) by streptokinase (SK) and urokinase (UK), and that these properties of anions can be correlated with their effects on the structure of GlujPg. In the case of activation by SK, a species of activator complex consisting of equimolar SK and GlujPg (SK-Glu]Pg*), that is sensitive to the presence of Cl- and fibrinogen (Fg), exists which decays to another complex of SK and GlujPg (SK-GlujPg'), the activity of which is not influenced by these effector molecules. The overall activation of GlujPg by SK-GlujPg* is inhibited by Cl- and stimulated by Fg. Kinetic studies indicate that Cl- is a mixed type inhibitor of the process, and Fg functions as a mixed type activator.The activation of GlujPg by both high- and low-molecular weight forms of UK is also inhibited by CL-, but is stimulated by e-amino caproic acid (EACA). The inhibition by Cl- does not occur in the presence of concentrations of EACA that saturate its weak binding sites on GlujPg, and the stimulation by EACA is maximally exhibited in the presence of CL-. Based upon structural studies of GlujPg in the presence of a variety of anions, such as Cl-, F-, I-, CNS-, OTs-, IO3 - and OAc-, we find that GlujPg can adopt a conformation (4.8S form) that is optimal to activation by UK, and one that is much less susceptible to such activation (5.8S form). The former occurs in certain salts and appears to correlate inversely with their ability to bind to the protein, or in the presence of any salt, plus saturating levels of EACA. The latter conformation is adopted in direct proportion with the ability of anions to interact with the protein, according to the Hofmeister series.In conclusion, we find that anions serve as inhibitors of activation of GlujPg, effects that are reversed by Fg (for SK) and EACA (for UK). This inhibition, which occurs at physiological concentrations of Cl-, serves to inhibit significantly plasminogen activation in normal circulation. Activation of plasminogen is enhanced upon its binding to surfaces (e.g., fibrin), via its lysine binding sites, an effect which may well contain a contribution from sequestration of Cl- from the protein.
Reports on the topic "OTX proteins"
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Barg, Rivka, Erich Grotewold, and Yechiam Salts. Regulation of Tomato Fruit Development by Interacting MYB Proteins. United States Department of Agriculture, January 2012. http://dx.doi.org/10.32747/2012.7592647.bard.
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Background to the topic: Early tomato fruit development is executed via extensive cell divisions followed by cell expansion concomitantly with endoreduplication. The signals involved in activating the different modes of growth during fruit development are still inadequately understood. Addressing this developmental process, we identified SlFSM1 as a gene expressed specifically during the cell-division dependent stages of fruit development. SlFSM1 is the founder of a class of small plant specific proteins containing a divergent SANT/MYB domain (Barg et al 2005). Before initiating this project, we found that low ectopic over-expression (OEX) of SlFSM1 leads to a significant decrease in the final size of the cells in mature leaves and fruits, and the outer pericarp is substantially narrower, suggesting a role in determining cell size and shape. We also found the interacting partners of the Arabidopsis homologs of FSM1 (two, belonging to the same family), and cloned their tomato single homolog, which we named SlFSB1 (Fruit SANT/MYB–Binding1). SlFSB1 is a novel plant specific single MYB-like protein, which function was unknown. The present project aimed at elucidating the function and mode of action of these two single MYB proteins in regulating tomato fruit development. The specific objectives were: 1. Functional analysis of SlFSM1 and its interacting protein SlFSB1 in relation to fruit development. 2. Identification of the SlFSM1 and/or SlFSB1 cellular targets. The plan of work included: 1) Detailed phenotypic, histological and cellular analyses of plants ectopically expressing FSM1, and plants either ectopically over-expressing or silenced for FSB1. 2) Extensive SELEX analysis, which did not reveal any specific DNA target of SlFSM1 binding, hence the originally offered ChIP analysis was omitted. 3) Genome-wide transcriptional impact of gain- and loss- of SlFSM1 and SlFSB1 function by Affymetrix microarray analyses. This part is still in progress and therefore results are not reported, 4) Search for additional candidate partners of SlFSB1 revealed SlMYBI to be an alternative partner of FSB1, and 5) Study of the physical basis of the interaction between SlFSM1 and SlFSB1 and between FSB1 and MYBI. Major conclusions, solutions, achievements: We established that FSM1 negatively affects cell expansion, particularly of those cells with the highest potential to expand, such as the ones residing inner to the vascular bundles in the fruit pericarp. On the other hand, FSB1 which is expressed throughout fruit development acts as a positive regulator of cell expansion. It was also established that besides interacting with FSM1, FSB1 interacts also with the transcription factor MYBI, and that the formation of the FSB1-MYBI complex is competed by FSM1, which recognizes in FSB1 the same region as MYBI does. Based on these findings a model was developed explaining the role of this novel network of the three different MYB containing proteins FSM1/FSB1/MYBI in the control of tomato cell expansion, particularly during fruit development. In short, during early stages of fruit development (Phase II), the formation of the FSM1-FSB1 complex serves to restrict the expansion of the cells with the greatest expansion potential, those non-dividing cells residing in the inner mesocarp layers of the pericarp. Alternatively, during growth phase III, after transcription of FSM1 sharply declines, FSB1, possibly through complexing with the transcription factor MYBI serves as a positive regulator of the differential cell expansion which drives fruit enlargement during this phase. Additionally, a novel mechanism was revealed by which competing MYB-MYB interactions could participate in the control of gene expression. Implications, both scientific and agricultural: The demonstrated role of the FSM1/FSB1/MYBI complex in controlling differential cell growth in the developing tomato fruit highlights potential exploitations of these genes for improving fruit quality characteristics. Modulation of expression of these genes or their paralogs in other organs could serve to modify leaf and canopy architecture in various crops.
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Meidan, Rina, and Robert Milvae. Regulation of Bovine Corpus Luteum Function. United States Department of Agriculture, March 1995. http://dx.doi.org/10.32747/1995.7604935.bard.
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The main goal of this research plan was to elucidate regulatory mechanisms controlling the development, function of the bovine corpus luteum (CL). The CL contains two different sterodigenic cell types and therefore it was necessary to obtain pure cell population. A system was developed in which granulosa and theca interna cells, isolated from a preovulatory follicle, acquired characteristics typical of large (LL) and small (SL) luteal cells, respectively, as judged by several biochemical and morphological criteria. Experiments were conducted to determine the effects of granulosa cells removal on subsequent CL function, the results obtained support the concept that granulosa cells make a substaintial contribution to the output of progesterone by the cyclic CL but may have a limited role in determining the functional lifespan of the CL. This experimental model was also used to better understand the contribution of follicular granulosa cells to subsequent luteal SCC mRNA expression. The mitochondrial cytochrome side-chain cleavage enzyme (SCC), which converts cholesterol to pregnenolone, is the first and rate-limiting enzyme of the steroidogenic pathway. Experiments were conducted to characterize the gene expression of P450scc in bovine CL. Levels of P450scc mRNA were higher during mid-luteal phase than in either the early or late luteal phases. PGF 2a injection decreased luteal P450scc mRNA in a time-dependent manner; levels were significantly reduced by 2h after treatment. CLs obtained from heifers on day 8 of the estrous cycle which had granulosa cells removed had a 45% reduction in the levels of mRNA for SCC enzymes as well as a 78% reduction in the numbers of LL cells. To characterize SCC expression in each steroidogenic cell type we utilized pure cell populations. Upon luteinization, LL expressed 2-3 fold higher amounts of both SCC enzymes mRNAs than SL. Moreover, eight days after stimulant removal, LL retained their P4 production capacity, expressed P450scc mRNA and contained this protein. In our attempts to establish the in vitro luteinization model, we had to select the prevulatory and pre-gonadotropin surge follicles. The ratio of estradiol:P4 which is often used was unreliable since P4 levels are high in atretic follicles and also in preovulatory post-gonadotropin follicles. We have therefore examined whether oxytocin (OT) levels in follicular fluids could enhance our ability to correctly and easily define follicular status. Based on E2 and OT concentrations in follicular fluids we could more accurately identify follicles that are preovulatory and post gonadotropin surge. Next we studied OT biosynthesis in granulosa cells, cells which were incubated with forskolin contained stores of the precursor indicating that forskolin (which mimics gonadotropin action) is an effective stimulator of OT biosynthesis and release. While studying in vitro luteinization, we noticed that IGF-I induced effects were not identical to those induced by insulin despite the fact that megadoses of insulin were used. This was the first indication that the cells may secrete IGF binding protein(s) which regonize IGFs and not insulin. In a detailed study involving several techniques, we characterized the species of IGF binding proteins secreted by luteal cells. The effects of exogenous polyunsaturated fatty acids and arachidonic acid on the production of P4 and prostanoids by dispersed bovine luteal cells was examined. The addition of eicosapentaenoic acid and arachidonic acid resulted in a dose-dependent reduction in basal and LH-stimulated biosynthesis of P4 and PGI2 and an increase in production of PGF 2a and 5-HETE production. Indomethacin, an inhibitor of arachidonic acid metabolism via the production of 5-HETE was unaffected. Results of these experiments suggest that the inhibitory effect of arachidonic acid on the biosynthesis of luteal P4 is due to either a direct action of arachidonic acid, or its conversion to 5-HETE via the lipoxgenase pathway of metabolism. The detailed and important information gained by the two labs elucidated the mode of action of factors crucially important to the function of the bovine CL. The data indicate that follicular granulosa cells make a major contribution to numbers of large luteal cells, OT and basal P4 production, as well as the content of cytochrome P450 scc. Granulosa-derived large luteal cells have distinct features: when luteinized, the cell no longer possesses LH receptors, its cAMP response is diminished yet P4 synthesis is sustained. This may imply that maintenance of P4 (even in the absence of a Luteotropic signal) during critical periods such as pregnancy recognition, is dependent on the proper luteinization and function of the large luteal cell.
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Weinberg, Zwi G., Adegbola Adesogan, Itzhak Mizrahi, Shlomo Sela, Kwnag Jeong, and Diwakar Vyas. effect of selected lactic acid bacteria on the microbial composition and on the survival of pathogens in the rumen in context with their probiotic effects on ruminants. United States Department of Agriculture, January 2014. http://dx.doi.org/10.32747/2014.7598162.bard.
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This research project was performed in context of the apparent probiotic effect of selected lactic acid bacteria (LAB) silage inoculants on the performance of ruminants (improved feed intake, faster live-weight gain, higher milk yields and improved feed efficiency). The overall objective was to find out how LAB affect ruminant performance. The project included several “chapters” as follows: 1. The effect of LAB silage inoculants on the survival of detrimental bacteria in rumen fluid, in vitro study (Weinberg et al., The Volcani Center). An in vitro model was developed to study the interaction between selected LAB and an E. coli strain tagged with green fluorescence protein (GFP) in buffered RF. Results indicated that both LAB inoculants and E. coli survived in the RF for several days; both LAB inoculants and LAB-treated silages did not affect survival of E. coli in rumen fluid in vitro. The effect of feeding baled wheat silages treated with or without three selected LAB silage inoculants on the performance of high-lactating cows (Weinberg et al., The Volcani Center). Treatments included control (no additive), Lacobacillusbuchneri40788 (LB), Lactobacillus plantarumMTD1 40027 (LP) and Pediococcuspentosaceus30168 (PP), each applied at 10⁶ cfu/g FM. The silages were included in the TMR of 32 high milking Holstein cows in a controlled feeding experiment. All baled silages were of good quality. The LB silage had the numerically highest acetic acid and were the most stable upon aerobic exposure. The cows fed the LB silages had the highest daily milk yields, percent milk fat and protein. The microbiome of baled wheat silages and changes during ensiling of wheat and corn (Sela et al., The Volcani Center). Bacterial community of the baled silages was dominated mainly of two genera in total, dominated by Lactobacillus and Clostridium_sensu_stricto_12 with 300 other genera at very low abundance. Fungal community was composed mainly of two genera in total, dominated by Candida and Monascuswith 20 other genera at very low abundance. In addition, changes in the microbiome during ensiling of wheat and corn with and without addition of L. plantarumMTD1 was studied in mini-silos. Overall 236 bacterial genera were identified in the fresh corn but after 3 months Lactobacillus outnumbered all other species by acquiring 95% of relative abundance. The wheat silage samples are still under analysis. The effect of applying LAB inoculants at ensiling on survival of E. coli O157:H7 in alfalfa and corn silages(Adesogan et al., University of Florida). E. coli (10⁵ cfu/g) was applied to fresh alfalfa and corn at ensiling with or without L. plantarumor L. buchneri. The pathogen was added again after about 3 moths at the beginning of an aerobic exposure period. The inoculants resulted in faster decrease in pH as compared with the control (no additives) or E. coli alone and therefore, the pathogen was eliminated faster from these silages. After aerobic exposure the pathogen was not detected in the LAB treated silages, whereas it was still present in the E. coli alone samples. 5. The effect of feeding corn silage treated with or without L. buchnerion shedding of E. coli O157:H7 by dairy cows (Adesogan et al., UFL). BARD Report - Project 4704 Page 2 of 12 Five hundred cows from the dairy herd of the University of Florida were screened for E. coli shedding, out of which 14 low and 13 high shedders were selected. These cows were fed a total mixed ration (TMR) which was inoculated with E. coli O157:H7 for 21 days. The TMR included corn silage treated with or without L. buchneri. The inoculated silages were more stable upon aerobic exposure than the control silages; the silage inoculant had no significant effect on any milk or cow blood parameters. However, the silage inoculant tended to reduce shedding of E. coli regardless of high or low shedders (p = 0.06). 6. The effect of feeding baled wheat silages treated with or without three selected LAB silage inoculants on the rumen microbiome (Mizrahi et al., BGU). Rumen fluid was sampled throughout the feeding experiment in which inoculated wheat silages were included in the rations. Microbial DNA was subsequently purified from each sample and the 16S rRNA was sequenced, thus obtaining an overview of the microbiome and its dynamic changes for each experimental treatment. We observed an increase in OTU richness in the group which received the baled silage inoculated with Lactobacillus Plantarum(LP). In contrast the group fed Lactobacillus buchneri(LB) inoculated silage resulted in a significant decrease in richness. Lower OTU richness was recently associated in lactating cows with higher performance (Ben Shabatet al., 2016). No significant clustering could be observed between the different inoculation treatments and the control in non metric multi-dimentional scaling, suggesting that the effect of the treatments is not the result of an overall modulation of the microbiome composition but possibly the result of more discrete interactions. Significant phylum level changes in composition also indicates that no broad changes in taxa identity and composition occurred under any treatment A more discrete modulation could be observed in the fold change of several taxonomic groups (genus level analysis), unique to each treatment, before and after the treatment. Of particular interest is the LB treated group, in which several taxa significantly decreased in abundance. BARD Report - Project 4704 Page 3 of 12