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Afshin Dowlati - One of the best experts on this subject based on the ideXlab platform.
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post transcriptional regulation of PIAS3 expression by mir 18a in malignant mesothelioma
Molecular Oncology, 2018Co-Authors: Karen S Mccoll, Nneha Sakre, Gary Wildey, Yanwen Chen, Afshin DowlatiAbstract:Protein inhibitor of activated STAT3 (PIAS3) is an endogenous suppressor of signal transducer and activator of transcription 3 (STAT3) signaling. By directly interacting with phosphorylated STAT3, PIAS3 can block the downstream transcriptional activity of STAT3, which is hyper-activated in various cancers. We previously reported that in malignant mesothelioma (MM), low PIAS3 expression is associated with increased STAT3 activation and correlates with poor patient survival, yet the regulatory mechanism(s) governing PIAS3 expression in MM remain unclear. Here, we demonstrate that PIAS3 protein expression does not correlate with its mRNA level in MM cell lines, indicating that PIAS3 expression is regulated at a post-transcriptional level. Inhibition of proteasomal degradation with MG132 (10 μm) or bortezomib (1 μm), alone and in combination, did not increase PIAS3 protein levels; furthermore, inhibition of protein synthesis by cycloheximide treatment did not decrease PIAS3 levels within 48 h, suggesting that PIAS3 expression is not actively regulated at a post-translational level. To determine whether miRNA (miRs) can translationally regulate PIAS3 expression, we combined miR microarray analysis with bioinformatic screening to identify candidate miRs, in MM cell lines with low PIAS3 expression, followed by luciferase reporter assays to validate miR regulation of the PIAS3 3'UTR. We identified miR-18a as a suppressor of PIAS3 expression that is upregulated in MM cells and whose inhibition can increase PIAS3 expression and suppress STAT3 activity. Moreover, we showed that miR-18a inhibition can decrease MM cell viability and that its expression is negatively correlated with MM patient survival. Taken together, these results suggest that targeting miR-18a may have therapeutic benefit in MM.
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abstract 4490 post transcriptional regulation on PIAS3 expression in malignant mesothelioma
Cancer Research, 2017Co-Authors: Karen S Mccoll, Nneha Sakre, Gary Wildey, Afshin DowlatiAbstract:Protein Inhibitor of Activated STAT3 (PIAS3) was originally identified as an endogenous suppressor of STAT3 activity which can specifically interact with activated STAT3 and block its downstream oncogenic effects. Previous studies from our lab have shown that low PIAS3 protein expression in mesothelioma tumors was associated with poor patient survival. Furthermore, low PIAS3 expression in mesothelioma cell lines correlated with higher STAT3 activity. Over-expression of PIAS3 decreased STAT3 activity and cell growth. These findings suggest that low PIAS3 expression may play an important role in mesothelioma tumorigenesis, thus understanding the regulatory mechanism(s) of PIAS3 expression may provide new therapeutic strategies in mesothelioma treatment. Initially, we examined PIAS3 expression by western blotting and RT-qPCR among six mesothelioma cell lines (H28, 211H, H2052, H2452, HAY, YOU) and found that while PIAS3 mRNA levels were relatively constant, PIAS3 protein expression was highly variable. This finding indicated a potential post-transcriptional regulation of PIAS3 expression in mesothelioma. To investigate this further, we first examined PIAS3 protein stability in the presence of proteasome inhibitors and cycloheximide (CHX). We observed no increase in PIAS3 protein levels during proteasome inhibition using either MG132 (10 μM) or bortezemib (1 μM) for up to 8 h in 211H, H2052 and H2452 cells, whereas TP53 protein expression was increased. Blocking translational protein synthesis with 50 or 100 μg/ml CHX for up to 24 h also produced little change in PIAS3 protein expression in mesothelioma cells, indicating that PIAS3 is a very stable protein. We next explored the PIAS3 3’UTR as a potential site for translational regulation. We initially utilized a miR microarray and computational analysis, followed by a PIAS3 3’UTR luciferase reporter assay, to screen miRNAs that are both increased in cells with low PIAS3 and have seed sequences targeting the PIAS3 3’UTR and identified miR-18a as our first candidate. Taken together, our study suggests that variable expression of PIAS3 protein in mesothelioma is regulated by translational control and not by protein stability. Citation Format: Tian He, Karen McColl, Nneha Sakre, Gary Wildey, Afshin Dowlati. Post-transcriptional regulation on PIAS3 expression in malignant mesothelioma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4490. doi:10.1158/1538-7445.AM2017-4490
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PIAS3 expression in squamous cell lung cancer is low and predicts overall survival
Cancer Medicine, 2015Co-Authors: R Abbas, Karen S Mccoll, Gary Wildey, Yanwen Chen, Adam Kresak, Michael Yang, Afshin DowlatiAbstract:Unlike lung adenocarcinoma, little progress has been made in the treatment of squamous cell lung carcinoma (SCC). The Cancer Genome Atlas (TCGA) has recently reported that receptor tyrosine kinase signaling pathways are altered in 26% of SCC tumors, validating the importance of downstream Signal Transducers and Activators of Transcription 3 (STAT3) activity as a prime therapeutic target in this cancer. In the present report we examine the status of an endogenous inhibitor of STAT3, called Protein Inhibitor of Activated STAT3 (PIAS3), in SCC and its potential role in this disease. We examine PIAS3 expression in SCC tumors and cell lines by immunohistochemistry of a tissue microarray and western blotting. PIAS3 mRNA expression and survival data are analyzed in the TCGA data set. SCC cell lines are treated with curcumin to regulate PIAS3 expression and cell growth. PIAS3 protein expression is decreased in a majority of lung SCC tumors and cell lines. Analysis of PIAS3 mRNA transcript levels demonstrated that low PIAS3 levels predicted poor survival; Cox regression analysis revealed a hazard ratio of 0.57 (95% CI: 0.37–0.87), indicating a decrease in the risk of death by 43% for every unit elevation in PIAS3 gene expression. Curcumin treatment increased endogenous PIAS3 expression and decreased cell growth and viability in Calu-1 cells, a model of SCC. Our results implicate PIAS3 loss in the pathology of lung SCC and raise the therapeutic possibility of upregulating PIAS3 expression as a single target that can suppress signaling from the multiple receptor tyrosine kinase receptors found to be amplified in SCC.
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low PIAS3 expression in malignant mesothelioma is associated with increased stat3 activation and poor patient survival
Clinical Cancer Research, 2014Co-Authors: Snehal Dabir, Amy Kluge, Gary Wildey, Adam Kresak, Michael Yang, Bernd Groner, Afshin DowlatiAbstract:Purpose: Deregulation of STAT3 activation is a hallmark of many cancer cells, and the underlying mechanisms are subject to intense investigation. We examined the extent of PIAS3 expression in mesothelioma cells and human tumor samples and determined the functional effects of PIAS3 expression on STAT3 signaling. Experimental design: We evaluated the expression of PIAS3 in mesothelioma tumors from patients and correlated the expression levels with the course of the disease. We also measured the effects of enhanced PIAS3 activity on STAT3 signaling, cellular growth, and viability in cultured mesothelioma cells. Results: Gene expression databases revealed that mesotheliomas have the lowest levels of PIAS3 transcripts among solid tumors. PIAS3 expression in human mesothelioma tumors is significantly correlated with overall survival intervals ( P = 0.058). The high expression of PIAS3 is predictive of a favorable prognosis and decreases the probability of death within one year after diagnosis by 44%. PIAS3 expression is functionally linked to STAT3 activation in mesothelioma cell lines. STAT3 downregulation with siRNA or enhanced expression of PIAS3 both inhibited mesothelioma cell growth and induced apoptosis. Mesothelioma cells are sensitive to curcumin and respond by the induction of PIAS3. Corroborative evidence has been obtained from STAT3 inhibition experiments. Exposure of the cells to a peptide derived from the PIAS3 protein that interferes with STAT3 function resulted in apoptosis induction and the inhibition of cell growth. Conclusion: These results suggest that PIAS3 protein expression impacts survival in patients with mesothelioma and that PIAS3 activation could become a therapeutic strategy. Clin Cancer Res; 20(19); 5124–32. ©2014 AACR .
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PIAS3 activates the intrinsic apoptotic pathway in non small cell lung cancer cells independent of p53 status
International Journal of Cancer, 2014Co-Authors: Snehal Dabir, Amy Kluge, Karen S Mccoll, Gary Wildey, Yu Liu, Minh Lam, Balazs Halmos, Afshin DowlatiAbstract:Protein inhibitor of activated signal transducer and activator of transcription 3 (STAT3) (PIAS3) is an endogenous inhibitor of STAT3 that negatively regulates STAT3 transcriptional activity and cell growth and demonstrates limited expression in the majority of human squamous cell carcinomas of the lung. In this study, we sought to determine whether PIAS3 inhibits cell growth in non-small cell lung cancer cell lines by inducing apoptosis. Our results demonstrate that overexpression of PIAS3 promotes mitochondrial depolarization, leading to cytochrome c release, caspase 9 and 3 activation and poly (ADP-ribose) polymerase cleavage. This intrinsic pathway activation was associated with decreased Bcl-xL expression and increased Noxa expression and was independent of p53 status. Furthermore, PIAS3 inhibition of STAT3 activity was also p53 independent. Microarray experiments were performed to discover STAT3-independent mediators of PIAS3-induced apoptosis by comparing the apoptotic gene expression signature induced by PIAS3 overexpression with that induced by STAT3 siRNA. The results showed that a subset of apoptotic genes was uniquely expressed only after PIAS3 expression. Thus, PIAS3 may represent a promising lung cancer therapeutic target because of its p53-independent efficacy and its potential to synergize with Bcl-2 targeted inhibitors.
Masahide Takahashi - One of the best experts on this subject based on the ideXlab platform.
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pias proteins are involved in the sumo 1 modification intracellular translocation and transcriptional repressive activity of ret finger protein
Experimental Cell Research, 2005Co-Authors: Tetsuo Matsuura, Yohei Shimono, Kumi Kawai, Hideki Murakami, Takeshi Urano, Yasumasa Niwa, Hidemi Goto, Masahide TakahashiAbstract:Abstract Ret finger protein (RFP) is a nuclear protein that is highly expressed in testis and in various tumor cell lines. RFP functions as a transcriptional repressor and associates with Enhancer of Polycomb 1 (EPC1), a member of the Polycomb group proteins, and Mi-2β, a main component of the nucleosome remodeling and deacetylase (NuRD) complex. We show that RFP binds with PIAS (protein inhibitor of activated STAT) proteins, PIAS1, PIAS3, PIASxα and PIASy at their carboxyl-terminal region and is covalently modified by SUMO-1 (sumoylation). PIAS proteins enhance the sumoylation of RFP in a dose-dependent manner and induce the translocation of RFP into nuclear bodies reminiscent of the PML bodies. In addition, co-expression of PIAS proteins or SUMO-1 strengthened the transcriptional repressive activity of RFP. Finally, our immunohistochemical results show that RFP, SUMO-1 and PIASy localize in a characteristic nuclear structure juxtaposed with the inner nuclear membrane (XY body) of primary spermatocytes in mouse testis. These results demonstrate that the intracellular location and the transcriptional activity of RFP are modified by PIAS proteins which possess SUMO E3 ligase activities and suggest that they may play a co-operative role in spermatogenesis.
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pias proteins are involved in the sumo 1 modification intracellular translocation and transcriptional repressive activity of ret finger protein
Experimental Cell Research, 2005Co-Authors: Tetsuo Matsuura, Yohei Shimono, Kumi Kawai, Hideki Murakami, Takeshi Urano, Yasumasa Niwa, Hidemi Goto, Masahide TakahashiAbstract:Ret finger protein (RFP) is a nuclear protein that is highly expressed in testis and in various tumor cell lines. RFP functions as a transcriptional repressor and associates with Enhancer of Polycomb 1 (EPC1), a member of the Polycomb group proteins, and Mi-2beta, a main component of the nucleosome remodeling and deacetylase (NuRD) complex. We show that RFP binds with PIAS (protein inhibitor of activated STAT) proteins, PIAS1, PIAS3, PIASxalpha and PIASy at their carboxyl-terminal region and is covalently modified by SUMO-1 (sumoylation). PIAS proteins enhance the sumoylation of RFP in a dose-dependent manner and induce the translocation of RFP into nuclear bodies reminiscent of the PML bodies. In addition, co-expression of PIAS proteins or SUMO-1 strengthened the transcriptional repressive activity of RFP. Finally, our immunohistochemical results show that RFP, SUMO-1 and PIASy localize in a characteristic nuclear structure juxtaposed with the inner nuclear membrane (XY body) of primary spermatocytes in mouse testis. These results demonstrate that the intracellular location and the transcriptional activity of RFP are modified by PIAS proteins which possess SUMO E3 ligase activities and suggest that they may play a co-operative role in spermatogenesis.
Snehal Dabir - One of the best experts on this subject based on the ideXlab platform.
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low PIAS3 expression in malignant mesothelioma is associated with increased stat3 activation and poor patient survival
Clinical Cancer Research, 2014Co-Authors: Snehal Dabir, Amy Kluge, Gary Wildey, Adam Kresak, Michael Yang, Bernd Groner, Afshin DowlatiAbstract:Purpose: Deregulation of STAT3 activation is a hallmark of many cancer cells, and the underlying mechanisms are subject to intense investigation. We examined the extent of PIAS3 expression in mesothelioma cells and human tumor samples and determined the functional effects of PIAS3 expression on STAT3 signaling. Experimental design: We evaluated the expression of PIAS3 in mesothelioma tumors from patients and correlated the expression levels with the course of the disease. We also measured the effects of enhanced PIAS3 activity on STAT3 signaling, cellular growth, and viability in cultured mesothelioma cells. Results: Gene expression databases revealed that mesotheliomas have the lowest levels of PIAS3 transcripts among solid tumors. PIAS3 expression in human mesothelioma tumors is significantly correlated with overall survival intervals ( P = 0.058). The high expression of PIAS3 is predictive of a favorable prognosis and decreases the probability of death within one year after diagnosis by 44%. PIAS3 expression is functionally linked to STAT3 activation in mesothelioma cell lines. STAT3 downregulation with siRNA or enhanced expression of PIAS3 both inhibited mesothelioma cell growth and induced apoptosis. Mesothelioma cells are sensitive to curcumin and respond by the induction of PIAS3. Corroborative evidence has been obtained from STAT3 inhibition experiments. Exposure of the cells to a peptide derived from the PIAS3 protein that interferes with STAT3 function resulted in apoptosis induction and the inhibition of cell growth. Conclusion: These results suggest that PIAS3 protein expression impacts survival in patients with mesothelioma and that PIAS3 activation could become a therapeutic strategy. Clin Cancer Res; 20(19); 5124–32. ©2014 AACR .
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PIAS3 activates the intrinsic apoptotic pathway in non small cell lung cancer cells independent of p53 status
International Journal of Cancer, 2014Co-Authors: Snehal Dabir, Amy Kluge, Karen S Mccoll, Gary Wildey, Yu Liu, Minh Lam, Balazs Halmos, Afshin DowlatiAbstract:Protein inhibitor of activated signal transducer and activator of transcription 3 (STAT3) (PIAS3) is an endogenous inhibitor of STAT3 that negatively regulates STAT3 transcriptional activity and cell growth and demonstrates limited expression in the majority of human squamous cell carcinomas of the lung. In this study, we sought to determine whether PIAS3 inhibits cell growth in non-small cell lung cancer cell lines by inducing apoptosis. Our results demonstrate that overexpression of PIAS3 promotes mitochondrial depolarization, leading to cytochrome c release, caspase 9 and 3 activation and poly (ADP-ribose) polymerase cleavage. This intrinsic pathway activation was associated with decreased Bcl-xL expression and increased Noxa expression and was independent of p53 status. Furthermore, PIAS3 inhibition of STAT3 activity was also p53 independent. Microarray experiments were performed to discover STAT3-independent mediators of PIAS3-induced apoptosis by comparing the apoptotic gene expression signature induced by PIAS3 overexpression with that induced by STAT3 siRNA. The results showed that a subset of apoptotic genes was uniquely expressed only after PIAS3 expression. Thus, PIAS3 may represent a promising lung cancer therapeutic target because of its p53-independent efficacy and its potential to synergize with Bcl-2 targeted inhibitors.
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abstract 847 PIAS3 induction of apoptosis is p53 independent and has stat3 independent mediators
Cancer Research, 2013Co-Authors: Snehal Dabir, Gary Wildey, Yu Liu, Afshin DowlatiAbstract:Protein inhibitor of activated STAT3 (PIAS3) is an endogenous inhibitor of STAT3 that negatively regulates STAT3 transcriptional activity and cell growth and demonstrates limited expression in the majority of human squamous cell carcinomas of the lung. In the present study we sought to determine if PIAS3 inhibits cell growth in non-small cell lung cancer (NSCLC) cell lines by induction of apoptosis and further determine the dependence of PIAS3 activity on p53 status by using both wild-type and p53-null cells. Our results demonstrate that over-expression of PIAS3 promotes caspase 3 activation and PARP cleavage. Furthermore, the expression of pro-survival family members BclXL and Bcl-2 is decreased. These effects were observed after both transient and regulated expression of exogenous PIAS3 and were independent of p53 status. PIAS3 inhibition of STAT3 luciferase activity was also p53 independent. Microarray experiments were performed to further investigate the STAT3-dependence of PIAS3-induced apoptosis by comparing its gene expression signature with that of STAT3 siRNA treated cells. IPA pathway analysis showed that a number of genes related to cell death were significantly increased by PIAS3. Furthermore, a subset of apoptotic genes, including CIDEC and DAPK2, were uniquely expressed only after PIAS3 expression and not after STAT3 siRNA. Thus, PIAS3 may represent a promising lung cancer therapeutic target because of its p53-independent efficacy as well as its potential to synergize with direct STAT3 inhibitors. Citation Format: Snehal Dabir, Yu Liu, Gary Wildey, Afshin Dowlati. PIAS3 induction of apoptosis is p53-independent and has STAT3-independent mediators. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 847. doi:10.1158/1538-7445.AM2013-847
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abstract 2249 induction of PIAS3 by curcumin as a novel treatment strategy in mesothelioma
Cancer Research, 2013Co-Authors: Snehal Dabir, Gary Wildey, Afshin DowlatiAbstract:Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC Curcumin, a natural drug derived from the spice turmeric, has been extensively studied as an anti-cancer agent. The mechanism of action behind this promising bioactivity of curcumin, previously unclear, is now beginning to emerge. Curcumin has been shown to inhibit STAT3 phosphorylation and activity in melanoma cells, ovarian and endometrial cancer cells and small-cell lung cancer cells. In many cancers constitutively activated STAT3 (Signal Transducers and Activators of Transcription 3) is essential for cell proliferation. In this study we demonstrate that four mesothelioma cell lines demonstrate high levels of active STAT3. The addition of curcumin can suppress mesothelioma cell growth and proliferation, demonstrating the STAT3-dependence of these cells. Interestingly, the inhibitory effect of curcumin on STAT3 appears to be mediated through an upregulation of an endogenous inhibitor of STAT3 called PIAS3 (protein inhibitor of activated STAT3). Thus, the significance of our results is that curcumin not only targets an effector of mesothelioma cell proliferation, STAT3, but does this by increasing the expression of its endogenous inhibitor, PIAS3. This result prompted ongoing studies to determine if PIAS3 levels are deficient in mesothelioma tumor specimens obtained from the National Virtual Mesothelioma bank. Taken together, our data support the idea that mesothelioma is a STAT3-driven cancer caused by a lack of PIAS3 expression and that strategies to increase endogenous PIAS3 expression will have tumor suppressor effects. The ability of curcumin to increase PIAS3 expression will give us a jump start on pursuing this strategy because it represents a bioactive lead compound with many available structural analogs. Citation Format: Snehal Dabir, Gary Wildey, Afshin Dowlati. Induction of PIAS3 by curcumin as a novel treatment strategy in mesothelioma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2249. doi:10.1158/1538-7445.AM2013-2249
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protein inhibitor of activated stat3 expression in lung cancer
Molecular Oncology, 2011Co-Authors: Amy Kluge, Snehal Dabir, Ilse Vlassenbroeck, Rosana Eisenberg, Afshin DowlatiAbstract:Protein Inhibitor of Activated Signal Transducer and Activators of Transcription 3 (PIAS3) is an endogenous inhibitor of STAT3 transcriptional activity. We have previously demonstrated the concentration-dependent negative regulatory effect of PIAS3 on STAT3 signaling and its capacity to decrease lung cancer proliferation and synergize with epidermal growth factor inhibition. We now investigate PIAS3 expression in both non-small cell lung cancer (NSCLC) cell lines and human resected NSCLC specimens. We also investigated the mechanism by which some lung cancers have significantly decreased PIAS3 expression. Expression of PIAS3 is variable in lung cancer cells lines with 2 of 3 squamous cell carcinoma (SCC) cell lines having no or little PIAS3 protein expression. Similarly, the majority of human SCCs of the lung lack PIAS3 expression by immunohistochemistry; this despite the finding that SCCs have significantly higher levels of PIAS3 mRNA compared to adenocarcinomas. High PIAS3 expression generally correlates with decreased phosphorylated STAT3 in both SCC cell lines and human specimens compatible with the negative regulatory effect of this protein on STAT3 signaling. To investigate this variable expression of PIAS3 we first performed sequencing of the PIAS3 gene that demonstrated single nucleotide polymorphisms but no mutations. Exposure of lung cancer cells to 5-azacytidine and trichostatin A results in a significant increase in PIAS3 mRNA and protein expression. However, methylation-specific PCR demonstrates a lack of CpG island methylation in the promoter region of PIAS3. Exposure of cells to an agent blocking proteosomal degradation results in a significant increase in PIAS3. Our data thus shows that SCC of the lung commonly lacks PIAS3 protein expression and that post-translational modifications may explain this finding in some cases. PIAS3 is a potential therapeutic molecule to target STAT3 pathway in lung cancer.
Wolfgang Wurst - One of the best experts on this subject based on the ideXlab platform.
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disruption of the murine piasx gene results in reduced testis weight
Journal of Molecular Endocrinology, 2005Co-Authors: Henrikki Santti, Laura Mikkonen, Sirpa J Hirvonensantti, F Vauti, M Perera, Ashish Anand, Markus Panhuysen, Giorgio Corte, Jorma Toppari, Wolfgang WurstAbstract:PIASx belongs to the PIAS protein family, the members of which modulate activities of several transcription factors and act as E3 ligases in the sumoylation pathway. The PIASx gene is highly expressed in testis, suggesting a role in spermatogenesis. To investigate the function of PIASx in vivo, we have disrupted the PIASx gene in mice. Interestingly, the knockout mice were viable and fertile. Despite the normal fertility, the testis weight of the mutant animals was reduced and their number of apoptotic testicular cells was increased. Also, the sperm count of mutant mice tended to be reduced, but the quality of their sperm cells was normal. No significant changes were observed in the serum levels of LH and FSH or in the intratesticular testosterone concentration between the knockout animals and their wild-type littermates. Compensatory increases in other PIAS protein mRNAs were not observed in the knockout mice. These results imply that PIASx is required quantitatively rather than qualitatively for normal spermatogenesis.
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disruption of the murine piasx gene results in reduced testis weight
Journal of Molecular Endocrinology, 2005Co-Authors: Henrikki Santti, Laura Mikkonen, Sirpa J Hirvonensantti, F Vauti, M Perera, Ashish Anand, Markus Panhuysen, Giorgio Corte, Jorma Toppari, Wolfgang WurstAbstract:PIASx belongs to the PIAS protein family, the members of which modulate activities of several transcription factors and act as E3 ligases in the sumoylation pathway. The PIASx gene is highly expressed in testis, suggesting a role in spermatogenesis. To investigate the function of PIASx in vivo, we have disrupted the PIASx gene in mice. Interestingly, the knockout mice were viable and fertile. Despite the normal fertility, the testis weight of the mutant animals was reduced and their number of apoptotic testicular cells was increased. Also, the sperm count of mutant mice tended to be reduced, but the quality of their sperm cells was normal. No significant changes were observed in the serum levels of LH and FSH or in the intratesticular testosterone concentration between the knockout animals and their wild-type littermates. Compensatory increases in other PIAS protein mRNAs were not observed in the knockout mice. These results imply that PIASx is required quantitatively rather than qualitatively for normal spermatogenesis.
Tomoko Komatsu - One of the best experts on this subject based on the ideXlab platform.
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small ubiquitin like modifier 1 sumo 1 modification of the synergy control motif of ad4 binding protein steroidogenic factor 1 ad4bp sf 1 regulates synergistic transcription between ad4bp sf 1 and sox9
Molecular Endocrinology, 2004Co-Authors: Tomoko Komatsu, Hirofumi Mizusaki, Tokuo Mukai, Hidesato Ogawa, Daichi Baba, Masahiro Shirakawa, Shigetsugu Hatakeyama, Keiichi I Nakayama, Hideki YamamotoAbstract:An orphan nuclear receptor, Ad4 binding protein/steroidogenic factor 1 (Ad4BP/SF-1), is essential for the development and function of steroidogenic tissues. To examine the transcriptional regulation of Ad4BP/SF-1, two-hybrid screening was performed, and the sumoylation [conjugation of a small ubiqutin-like modifier (SUMO-1)] components Ubc9, protein inhibitor of activated STAT 1 (PIAS1), and protein inhibitor of activated STAT 3 (PIAS3) were isolated. Cultured cell and in vitro studies revealed that Ad4BP/SF-1 is sumoylated at K119 and K194. Because K194 lies within the synergy control (SC) motif defined to repress synergistic transcription from promoters containing multiple binding sites, correlation between the functions of the SC motif and sumoylation was investigated. The K194R mutant of Ad4BP/SF-1, which cannot be sumoylated, showed enhanced synergistic transcription from a promoter containing multiple Ad4/SF-1 sites, suggesting that sumoylation is necessary for repression of transcriptional synergy ...