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
目的:探究溴结构域蛋白4(bromodomain-containing protein 4,BRD4)在心肌梗死后心脏损伤中的作用。方法:通过分析公共数据,明确心肌梗死小鼠心脏组织中BRD4在整体和以及各细胞群中的表达变化。构建心肌梗死小鼠模型,设立空白对照组(WT...目的:探究溴结构域蛋白4(bromodomain-containing protein 4,BRD4)在心肌梗死后心脏损伤中的作用。方法:通过分析公共数据,明确心肌梗死小鼠心脏组织中BRD4在整体和以及各细胞群中的表达变化。构建心肌梗死小鼠模型,设立空白对照组(WT组),心肌梗死组(MI组),药物组(JQ1组,ABBV-744组),术后第6天腹腔注射BRD4抑制剂JQ1或灌胃二代抑制剂ABBV-744,持续22天。MI术后4周,小动物超声影像系统检测小鼠心功能,检测小鼠质量、心脏质量与胫骨长度,天狼星红染色评估梗死区纤维化程度,WGA染色检测心肌细胞横截面积。结果:与心肌梗死组相比,BRD4抑制剂组能够显著改善术后心功能障碍(P<0.01)。转录组学数据表明,BRD4在心肌梗死损伤区域持续高表达。单细胞数据显示,心肌梗死后,成纤维细胞中BRD4阳性细胞比例显著增加,并且在心肌梗死后7、14、30d的成纤维细胞中,BRD4表达持续上调。与心肌梗死组相比,BRD4抑制剂组显著减轻心脏纤维化(P <0.01)。与一代药物组相比,二代药物组心脏纤维化程度显著降低(P<0.01)。结论:抑制表观转录因子BRD4可减轻心肌梗死后心脏损伤,抑制心脏纤维化,并改善心功能。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.
文摘目的:探究溴结构域蛋白4(bromodomain-containing protein 4,BRD4)在心肌梗死后心脏损伤中的作用。方法:通过分析公共数据,明确心肌梗死小鼠心脏组织中BRD4在整体和以及各细胞群中的表达变化。构建心肌梗死小鼠模型,设立空白对照组(WT组),心肌梗死组(MI组),药物组(JQ1组,ABBV-744组),术后第6天腹腔注射BRD4抑制剂JQ1或灌胃二代抑制剂ABBV-744,持续22天。MI术后4周,小动物超声影像系统检测小鼠心功能,检测小鼠质量、心脏质量与胫骨长度,天狼星红染色评估梗死区纤维化程度,WGA染色检测心肌细胞横截面积。结果:与心肌梗死组相比,BRD4抑制剂组能够显著改善术后心功能障碍(P<0.01)。转录组学数据表明,BRD4在心肌梗死损伤区域持续高表达。单细胞数据显示,心肌梗死后,成纤维细胞中BRD4阳性细胞比例显著增加,并且在心肌梗死后7、14、30d的成纤维细胞中,BRD4表达持续上调。与心肌梗死组相比,BRD4抑制剂组显著减轻心脏纤维化(P <0.01)。与一代药物组相比,二代药物组心脏纤维化程度显著降低(P<0.01)。结论:抑制表观转录因子BRD4可减轻心肌梗死后心脏损伤,抑制心脏纤维化,并改善心功能。
