POU transcription factor OCT4 not only plays an essential role in maintaining the pluripotent and self-renewing state of embryonic stem （ES） cells but also acts as a cell fate determinant through a gene dosage effec...POU transcription factor OCT4 not only plays an essential role in maintaining the pluripotent and self-renewing state of embryonic stem （ES） cells but also acts as a cell fate determinant through a gene dosage effect. However, the molecular mechanisms that control the intracellular OCT4 protein level remain elusive. Here, we report that human WWP2, an E3 ubiquitin （Ub）-protein ligase, interacts with OCT4 specifically through its WW domain and enhances Ub modification of OCT4 both in vitro and in vivo. We first demonstrated that endogenous OCT4 in hu- man ES cells can be post-translationally modified by Ub. Furthermore, we found that WWP2 promoted degradation of OCT4 through the 26S proteasome in a dosage-dependent manner, and the active site cysteine residue of WWP2 was required for both its enzymatic activity and proteolytic effect on OCT4. Remarkably, our data show that the en- dogenous OCT4 protein level was significantly elevated when WWP2 expression was downregulated by specific RNA interference （RNAi）, suggesting that WWP2 is an important regulator for maintaining a proper OCT4 protein level in human ES cells. Moreover, northern blot analysis showed that the WWP2 transcript was widely present in diverse human tissues/organs and highly expressed in undifferentiated human ES cells. However, its expression level was quickly decreased after human ES cells differentiated, indicating that WWP2 expression might be developmentally regulated. Our findings demonstrate that WWP2 is an important regulator of the OCT4 protein level in human ES cells.展开更多
Kruppel-like factor 4（Klf4） is a zinc finger transcription factor and plays crucial roles in Xenopus embryogenesis.However, its regulation during embryogenesis is still unclear. Here, we report that Tcf711, a key do...Kruppel-like factor 4（Klf4） is a zinc finger transcription factor and plays crucial roles in Xenopus embryogenesis.However, its regulation during embryogenesis is still unclear. Here, we report that Tcf711, a key downstream transducer of the Wnt signaling pathway, could promote Klf4 transcription and stimulate Klf4 promoter activity in early Xenopus embryos. Furthermore, cycloheximide treatment showed a direct effect on Klf4 transcription facilitated by Tcf711. Moreover, the dominant negative form of Tcf711（dnTcf711）, which lacks N-terminus of the β-catenin binding motif, could still activate Klf4 transcription, suggesting that this regulation is Wnt/β-catenin independent.Taken together, our results demonstrate that Tcf711 lies upstream of Klf4 to maintain its expression level during Xenopus embryogenesis.展开更多
Specificity protein(Sp)transcription factors(TFs)Sp1,Sp3 and Sp4,and the orphan nuclear receptor 4A1(NR4A1)are highly expressed in pancreatic tumors and Sp1 is a negative prognostic factor for pancreatic cancer patien...Specificity protein(Sp)transcription factors(TFs)Sp1,Sp3 and Sp4,and the orphan nuclear receptor 4A1(NR4A1)are highly expressed in pancreatic tumors and Sp1 is a negative prognostic factor for pancreatic cancer patient survival.Results of knockdown and overexpression of Sp1,Sp3 and Sp4 in pancreatic and other cancer lines show that these TFs are individually pro-oncogenic factors and loss of one Sp TF is not compensated by other members.NR4A1 is also a prooncogenic factor and both NR4A1 and Sp TFs exhibit similar functions in pancreatic cancer cells and regulate cell growth,survival,migration and invasion.There is also evidence that Sp TFs and NR4A1 regulate some of the same genes including survivin,epidermal growth factor receptor,PAX3-FOXO1,α5-andα6-integrins,β1-,β3-andβ4-integrins;this is due to NR4A1 acting as a cofactor and mediating NR4A1/Sp1/4-regulated gene expression through GC-rich gene promoter sites.Several studies show that drugs targeting Sp downregulation or NR4A1 antagonists are highly effective inhibitors of Sp/NR4A1-regulated pathways and genes in pancreatic and other cancer cells,and the triterpenoid celastrol is a novel dual-acting agent that targets both Sp TFs and NR4A1.展开更多
Genetic variants within or near the transcription factor 4 gene(TCF4)are robustly implicated in psychiatric disorders including schizophrenia.However,the biological pleiotropy poses considerable obstacles to dissect t...Genetic variants within or near the transcription factor 4 gene(TCF4)are robustly implicated in psychiatric disorders including schizophrenia.However,the biological pleiotropy poses considerable obstacles to dissect the potential relationship between TCF4 and those highly heterogeneous diseases.Through integrative transcriptomic analysis,we demonstrated that TCF4 is preferentially expressed in cortical interneurons during early brain development.Therefore,disruptions of interneuron development might be the underlying contribution of TCF4 perturbation to a range of neurodevelopmental disorders.Here,we performed chromatin immunoprecipitation sequencing(ChIP-seq)of TCF4 on human medial ganglionic eminence-like organoids(hMGEOs)to identify genome-wide TCF4 binding sites,followed by integration of multi-omics data from human fetal brain.We observed preferential expression of the isoform TCF4-B over TCF4-A.De novo motif analysis found that the identified 5916 TCF4 binding sites are significantly enriched for the E-box sequence.The predicted TCF4 targets in general have positively correlated expression levels with TCF4 in the cortical interneurons,and are primarily involved in biological processes related to neurogenesis.Interestingly,we found that TCF4 interacts with non-bHLH proteins such as FOS/JUN,which may underlie the functional specificity of TCF4 in hMGEOs.This study highlights the regulatory role of TCF4 in interneuron development and provides compelling evidence to support the biological rationale linking TCF4 to the developing cortical interneuron and psychiatric disorders.展开更多
An Amh promoter driving expression of a reporter gene (d2EGFP) has been used to analyze the role of two specific promoter transcription factor binding elements. In addition a downstream (3’) enhancer (DE) was also in...An Amh promoter driving expression of a reporter gene (d2EGFP) has been used to analyze the role of two specific promoter transcription factor binding elements. In addition a downstream (3’) enhancer (DE) was also investigated. The transcription factors GATA-1 and GATA-4 had opposite effects, the former being incremental and the latter decremental. The quantitative balance between these two factors may provide a degree of control over the level of gene expression.展开更多
Hepatocyte nuclear factor 4-alpha(HNF4α)is a highly conserved member of nuclear receptor superfamily of ligand-dependent transcription factors that is expressed in liver and gastrointestinal organs(pancreas,stomach,a...Hepatocyte nuclear factor 4-alpha(HNF4α)is a highly conserved member of nuclear receptor superfamily of ligand-dependent transcription factors that is expressed in liver and gastrointestinal organs(pancreas,stomach,and intestine).In liver,HNF4αis best known for its role as a master regulator of liver-specific gene expression and essential for adult and fetal liver function.Dysregulation of HNF4αexpression has been associated with many human diseases such as ulcerative colitis,colon cancer,maturity-onset diabetes of the young,liver cirrhosis,and hepatocellular carcinoma.However,the precise role of HNF4αin the etiology of these human pathogenesis is not well understood.Limited information is known about the role of HNF4αisoforms in liver and gastrointestinal disease progression.There is,therefore,a critical need to know how disruption of the expression of these isoforms may impact on disease progression and phenotypes.In this review,we will update our current understanding on the role of HNF4αin human liver and gastrointestinal diseases.We further provide additional information on possible use of HNF4αas a target for potential therapeutic approaches.展开更多
AIM： To characterize the proliferative capacity of pterygial epithelium in different regions（head, neck and body） of pterygium and explore the function of transcription factor 4（TCF4） in pterygium proliferation.M...AIM： To characterize the proliferative capacity of pterygial epithelium in different regions（head, neck and body） of pterygium and explore the function of transcription factor 4（TCF4） in pterygium proliferation.METHODS： Thirty pterygium tissues and 10 normal conjunctival tissues were obtained from Zhongshan Ophthalmic Center（ZOC） and Guangdong Eye Bank, respectively. Proliferative capacity of head, neck and body in pterygial epithelium was measured using clonal analysis, fold growth analysis and expression profile of proliferative markers revealed by immunofluorescent staining and real-time PCR. The expression of TCF4 was highlighted by double immunofluorescent staining with other proliferation related markers such as proliferating cell nuclear antigen（PCNA） and ATP-binding cassette subfamily G member 2（ABCG2）.RESULTS： The proliferative potential of pterygial epithelium was higher than that of normal conjunctival epithelium. High expression levels of proliferative markers（P63α, PCNA and ABCG2） in pterygial body epithelium were observed in immunofluorescent staining and real-time PCR（P〈0.05）. Also, epithelial cells isolated from pterygial body demonstrated higher proliferative capacity in clonal analysis and fold growth analysis, than those isolated from the head and neck regions. The TCF4 expression in pterygial epithelium was similar to other proliferative markers（P63α, PCNA and ABCG2）, as higher in pterygial body than head and neck. Moreover, TCF4 showed coexpression with other proliferation-related markers（PCNA and ABCG2） in the double immunofluorescent staining experiment.CONCLUSION： The proliferative capacity in pterygial body epithelium is prominent than the head and neck regions, and upregulated TCF4 may be associated with enhanced proliferation in the pterygium.展开更多
基金Acknowledgments We are grateful to Dr DA Melton （Harvard University） for shar- ing his human ES cells with us. The study was supported by grants from the National High Technology Research and Development Program of China （2006CB943900）, the National Natural Science Foundation of China （General Program, 30500088）, the Shang- hai Jiao Tong University School of Medicine, and the Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences. The study was also supported by the Shanghai Leading Academic Deciline Project （S30201）.
文摘POU transcription factor OCT4 not only plays an essential role in maintaining the pluripotent and self-renewing state of embryonic stem （ES） cells but also acts as a cell fate determinant through a gene dosage effect. However, the molecular mechanisms that control the intracellular OCT4 protein level remain elusive. Here, we report that human WWP2, an E3 ubiquitin （Ub）-protein ligase, interacts with OCT4 specifically through its WW domain and enhances Ub modification of OCT4 both in vitro and in vivo. We first demonstrated that endogenous OCT4 in hu- man ES cells can be post-translationally modified by Ub. Furthermore, we found that WWP2 promoted degradation of OCT4 through the 26S proteasome in a dosage-dependent manner, and the active site cysteine residue of WWP2 was required for both its enzymatic activity and proteolytic effect on OCT4. Remarkably, our data show that the en- dogenous OCT4 protein level was significantly elevated when WWP2 expression was downregulated by specific RNA interference （RNAi）, suggesting that WWP2 is an important regulator for maintaining a proper OCT4 protein level in human ES cells. Moreover, northern blot analysis showed that the WWP2 transcript was widely present in diverse human tissues/organs and highly expressed in undifferentiated human ES cells. However, its expression level was quickly decreased after human ES cells differentiated, indicating that WWP2 expression might be developmentally regulated. Our findings demonstrate that WWP2 is an important regulator of the OCT4 protein level in human ES cells.
基金supported by the Start-up Funding of Henan University of Science and Technology(13480027) to Q. C.the Key Science Foundation of Nanjing Medical University(2015NJMUZD002)+2 种基金the Natural Science Foundation of Higher Education Institutions of Jiangsu Province(16KJB-180020)Natural Science Foundation of Jiangsu Province (BK20171053)National Natural Science Funds of China (81702747) to C.L
文摘Kruppel-like factor 4（Klf4） is a zinc finger transcription factor and plays crucial roles in Xenopus embryogenesis.However, its regulation during embryogenesis is still unclear. Here, we report that Tcf711, a key downstream transducer of the Wnt signaling pathway, could promote Klf4 transcription and stimulate Klf4 promoter activity in early Xenopus embryos. Furthermore, cycloheximide treatment showed a direct effect on Klf4 transcription facilitated by Tcf711. Moreover, the dominant negative form of Tcf711（dnTcf711）, which lacks N-terminus of the β-catenin binding motif, could still activate Klf4 transcription, suggesting that this regulation is Wnt/β-catenin independent.Taken together, our results demonstrate that Tcf711 lies upstream of Klf4 to maintain its expression level during Xenopus embryogenesis.
基金Supported by Houston Methodist Cancer Center Innovation Award。
文摘Specificity protein(Sp)transcription factors(TFs)Sp1,Sp3 and Sp4,and the orphan nuclear receptor 4A1(NR4A1)are highly expressed in pancreatic tumors and Sp1 is a negative prognostic factor for pancreatic cancer patient survival.Results of knockdown and overexpression of Sp1,Sp3 and Sp4 in pancreatic and other cancer lines show that these TFs are individually pro-oncogenic factors and loss of one Sp TF is not compensated by other members.NR4A1 is also a prooncogenic factor and both NR4A1 and Sp TFs exhibit similar functions in pancreatic cancer cells and regulate cell growth,survival,migration and invasion.There is also evidence that Sp TFs and NR4A1 regulate some of the same genes including survivin,epidermal growth factor receptor,PAX3-FOXO1,α5-andα6-integrins,β1-,β3-andβ4-integrins;this is due to NR4A1 acting as a cofactor and mediating NR4A1/Sp1/4-regulated gene expression through GC-rich gene promoter sites.Several studies show that drugs targeting Sp downregulation or NR4A1 antagonists are highly effective inhibitors of Sp/NR4A1-regulated pathways and genes in pancreatic and other cancer cells,and the triterpenoid celastrol is a novel dual-acting agent that targets both Sp TFs and NR4A1.
基金funded by the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(Grant No.17KJB180009)to M.L.the Natural Science Foundation of Jiangsu Province(Grant No.BK20171062)to M.L.,the National Natural Science Foundation of China(Grant No.81701320)to M.L.We appreciate comments from the editor and anonymous reviewers.
文摘Genetic variants within or near the transcription factor 4 gene(TCF4)are robustly implicated in psychiatric disorders including schizophrenia.However,the biological pleiotropy poses considerable obstacles to dissect the potential relationship between TCF4 and those highly heterogeneous diseases.Through integrative transcriptomic analysis,we demonstrated that TCF4 is preferentially expressed in cortical interneurons during early brain development.Therefore,disruptions of interneuron development might be the underlying contribution of TCF4 perturbation to a range of neurodevelopmental disorders.Here,we performed chromatin immunoprecipitation sequencing(ChIP-seq)of TCF4 on human medial ganglionic eminence-like organoids(hMGEOs)to identify genome-wide TCF4 binding sites,followed by integration of multi-omics data from human fetal brain.We observed preferential expression of the isoform TCF4-B over TCF4-A.De novo motif analysis found that the identified 5916 TCF4 binding sites are significantly enriched for the E-box sequence.The predicted TCF4 targets in general have positively correlated expression levels with TCF4 in the cortical interneurons,and are primarily involved in biological processes related to neurogenesis.Interestingly,we found that TCF4 interacts with non-bHLH proteins such as FOS/JUN,which may underlie the functional specificity of TCF4 in hMGEOs.This study highlights the regulatory role of TCF4 in interneuron development and provides compelling evidence to support the biological rationale linking TCF4 to the developing cortical interneuron and psychiatric disorders.
文摘An Amh promoter driving expression of a reporter gene (d2EGFP) has been used to analyze the role of two specific promoter transcription factor binding elements. In addition a downstream (3’) enhancer (DE) was also investigated. The transcription factors GATA-1 and GATA-4 had opposite effects, the former being incremental and the latter decremental. The quantitative balance between these two factors may provide a degree of control over the level of gene expression.
文摘Hepatocyte nuclear factor 4-alpha(HNF4α)is a highly conserved member of nuclear receptor superfamily of ligand-dependent transcription factors that is expressed in liver and gastrointestinal organs(pancreas,stomach,and intestine).In liver,HNF4αis best known for its role as a master regulator of liver-specific gene expression and essential for adult and fetal liver function.Dysregulation of HNF4αexpression has been associated with many human diseases such as ulcerative colitis,colon cancer,maturity-onset diabetes of the young,liver cirrhosis,and hepatocellular carcinoma.However,the precise role of HNF4αin the etiology of these human pathogenesis is not well understood.Limited information is known about the role of HNF4αisoforms in liver and gastrointestinal disease progression.There is,therefore,a critical need to know how disruption of the expression of these isoforms may impact on disease progression and phenotypes.In this review,we will update our current understanding on the role of HNF4αin human liver and gastrointestinal diseases.We further provide additional information on possible use of HNF4αas a target for potential therapeutic approaches.
基金Supported by National Natural Science Foundation of China(No.81670823)
文摘AIM： To characterize the proliferative capacity of pterygial epithelium in different regions（head, neck and body） of pterygium and explore the function of transcription factor 4（TCF4） in pterygium proliferation.METHODS： Thirty pterygium tissues and 10 normal conjunctival tissues were obtained from Zhongshan Ophthalmic Center（ZOC） and Guangdong Eye Bank, respectively. Proliferative capacity of head, neck and body in pterygial epithelium was measured using clonal analysis, fold growth analysis and expression profile of proliferative markers revealed by immunofluorescent staining and real-time PCR. The expression of TCF4 was highlighted by double immunofluorescent staining with other proliferation related markers such as proliferating cell nuclear antigen（PCNA） and ATP-binding cassette subfamily G member 2（ABCG2）.RESULTS： The proliferative potential of pterygial epithelium was higher than that of normal conjunctival epithelium. High expression levels of proliferative markers（P63α, PCNA and ABCG2） in pterygial body epithelium were observed in immunofluorescent staining and real-time PCR（P〈0.05）. Also, epithelial cells isolated from pterygial body demonstrated higher proliferative capacity in clonal analysis and fold growth analysis, than those isolated from the head and neck regions. The TCF4 expression in pterygial epithelium was similar to other proliferative markers（P63α, PCNA and ABCG2）, as higher in pterygial body than head and neck. Moreover, TCF4 showed coexpression with other proliferation-related markers（PCNA and ABCG2） in the double immunofluorescent staining experiment.CONCLUSION： The proliferative capacity in pterygial body epithelium is prominent than the head and neck regions, and upregulated TCF4 may be associated with enhanced proliferation in the pterygium.
