Project description:Self-renewal and pluripotency in human embryonic stem cells (hESCs) depends upon the function of a remarkably small number of master transcription factors (TFs) that include OCT4, SOX2, and NANOG. Endogenous factors that regulate and maintain the expression of master TFs in hESCs remain largely unknown and/or uncharacterized. We use a genome-wide, proteomics approach to identify proteins associated with the OCT4 enhancer. We identify known OCT4 regulators, plus a subset of potential regulators including a zinc finger protein, ZNF207, that plays diverse roles during development. In hESCs, ZNF207 partners with master pluripotency TFs to govern self-renewal and pluripotency while simultaneously controlling commitment of cells towards ectoderm through direct regulation of neuronal TFs, including OTX2. The distinct roles of ZNF207 during differentiation occur via isoform switching. Thus, a distinct isoform of ZNF207 functions in hESCs at the nexus that balances pluripotency and differentiation to ectoderm.
Project description:Self-renewal and pluripotency in human embryonic stem cells (hESCs) depends upon the function of a remarkably small number of master transcription factors (TFs) that include OCT4, SOX2, and NANOG. Endogenous factors that regulate and maintain the expression of master TFs in hESCs remain largely unknown and/or uncharacterized. We use a genome-wide, proteomics approach to identify proteins associated with the OCT4 enhancer. We identify known OCT4 regulators, plus a subset of potential regulators including a zinc finger protein, ZNF207, that plays diverse roles during development. In hESCs, ZNF207 partners with master pluripotency TFs to govern self-renewal and pluripotency while simultaneously controlling commitment of cells towards ectoderm through direct regulation of neuronal TFs, including OTX2. The distinct roles of ZNF207 during differentiation occur via isoform switching. Thus, a distinct isoform of ZNF207 functions in hESCs at the nexus that balances pluripotency and differentiation to ectoderm.
Project description:Elucidating the mechanism of self-renewal and pluripotency maintenance of human embryonic stem cells (hESCs) is of great significance in basic research and clinical applications. Long non-coding RNAs (lncRNAs) have been shown to play a key role in the self-renewal and pluripotency maintenance of hESCs. We previously reported that the lncRNA ESRG, which is highly expressed in undifferentiated hESCs, can interact with the replication licensing factor MCM2 and inhibit the p53 pathway to maintain the self-renewal and pluripotency of hPSCs. In addition to MCM2, RNA pull-down mass spectrometry showed that ESRG could also bind to other proteins, among which heterogeneous nuclear ribonucleoprotein A1 (HNRNPA1) attracted our attention. In this study, we show that HNRNPA1 can maintain self-renewal and pluripotency of hESCs. ESRG binds to and stabilizes HNRNPA1 protein through the ubiquitin-proteasome pathway. In addition, knockdown of ESRG or HNRNPA1 resulted in alternative splicing of TCF3, which originally and primarily encodes E12, to mainly encode E47 and inhibit CDH1 expression. HNRNPA1 could rescue the biological function changes of hESCs caused by ESRG knockdown or overexpression. Our results suggest that ESRG regulates the alternative splicing of TCF3 to affect CDH1 expression and maintain hESCs self-renewal and pluripotency by binding and stabilizing HNRNPA1 protein. This study lays a good foundation for exploring the new molecular regulatory mechanism by which ESRG maintains hESCs self-renewal and pluripotency.
Project description:Embryonic stem cell (ESC) self-renewal and differentiation are governed by a broad-ranging regulatory network. Although the transcriptional regulatory mechanisms involved have been investigated extensively, post-transcriptional regulation is still poorly understood. Here we describe a critical role of the THO complex in ESC self-renewal and differentiation. We show that THO preferentially interacts with pluripotency gene transcripts through Thoc5, and is required for self-renewal at least in part by regulating their export and expression. During differentiation, THO loses its interaction with those transcripts due to reduced Thoc5 expression, leading to decreased expression of pluripotency proteins that facilitates exit from self-renewal. THO is also important for the establishment of pluripotency, as its depletion inhibits somatic cell reprogramming and blastocyst development. Together, our data indicate that THO regulates pluripotency gene mRNA export to control ESC self-renewal and differentiation, and therefore uncover a role for this aspect of post-transcriptional regulation in stem cell fate specification. mouse J1 cells were transfected with non-targeting (NT), Thoc2, and Thoc5 siRNAs. Total RNA was isolated 96 hours after transfection.
Project description:Embryonic stem cell (ESC) self-renewal and differentiation is governed by a comprehensive regulatory network. Although the transcriptional regulation has been extensively investigated, post-transcriptional mechanisms controlling the ESC state are poorly understood. Here we describe a critical role of the THO complex in ESC self-renewal and differentiation. We show that THO preferentially interacts with pluripotency gene transcripts through Thoc5, and is required for self-renewal by regulating their export and expression. During differentiation, THO loses its interaction with those transcripts due to reduced Thoc5 expression, which leads to decreased expression of pluripotency proteins and facilitates differentiation. Finally, THO is also important for the establishment of pluripotency, as its depletion inhibits somatic cell reprogramming and blastocyst development. Together, our data indicates that THO regulates pluripotency gene mRNA export to control ESC self-renewal and differentiation, and uncovers a novel mechanism of post-transcriptional regulation in stem cell fate specification. RNA IP was conducted by use of antibody against Thoc2, the precipitated RNA was used to generate library using illumina Kit, and subsequently sequenced by miSeq
Project description:Alternative RNA splicing (AS) regulates proteome diversity, including isoform-specific expression of several pluripotency genes. Here, we integrated global gene expression and proteomic analyses and identified a molecular signature suggesting a central role for AS in maintaining human pluripotent stem cell (hPSC) self-renewal. We demonstrate the splicing factor SFRS2 is an OCT4 target gene required for pluripotency. SFRS2 regulates AS of the methyl-CpG-binding protein MBD2, whose isoforms play opposing roles in maintenance of, and reprogramming to, pluripotency. While both MDB2a and MBD2c are enriched at the OCT4 and NANOG promoters, MBD2a preferentially interacts with repressive NuRD chromatin remodeling factors and promotes hPSC differentiation, whereas overexpression of MBD2c enhances reprogramming of fibroblasts to pluripotency. The miR-301 and miR-302 families provide additional regulation by targeting SFRS2 and MDB2a. These data suggest that OCT4, SFRS2, and MBD2 participate in a positive feedback loop, regulating proteome diversity complexity in support of hPSC self-renewal and reprogramming. We isolated RNA from human fibroblasts and human embryonic stem cells for hybridization to the Affymetrix gene expression microarrays.
Project description:Embryonic stem cell (ESC) self-renewal and differentiation are governed by a broad-ranging regulatory network. Although the transcriptional regulatory mechanisms involved have been investigated extensively, post-transcriptional regulation is still poorly understood. Here we describe a critical role of the THO complex in ESC self-renewal and differentiation. We show that THO preferentially interacts with pluripotency gene transcripts through Thoc5, and is required for self-renewal at least in part by regulating their export and expression. During differentiation, THO loses its interaction with those transcripts due to reduced Thoc5 expression, leading to decreased expression of pluripotency proteins that facilitates exit from self-renewal. THO is also important for the establishment of pluripotency, as its depletion inhibits somatic cell reprogramming and blastocyst development. Together, our data indicate that THO regulates pluripotency gene mRNA export to control ESC self-renewal and differentiation, and therefore uncover a role for this aspect of post-transcriptional regulation in stem cell fate specification.
Project description:Human exploration of outer space will inevitably require human reproduction and development in the space environment. Embryonic stem cells (ESCs) are widely employed to study mammalian development and reproduction for their characteristics of indefinite self-renewal and pluripotency. Due to the lack of experimental opportunities and related techniques, studies of the effects of microgravity on the self-renewal and differentiation of ESCs are mostly descriptive, with in-depth mechanistic studies remaining scarce. Here we show in both mouse and human ESCs that simulated microgravity (SMG)-induced stress regulates the self-renewal and pluripotency in a conserved mechanism. Specifically, SMG upregulates the expression of heat shock protein (HSP) and/or HSF1 genes, thereby increasing the expression of core pluripotency factors and the activity of the Wnt pathway. In mESCs, the upregulation of Hsps and Hsf1 genes by SMG increased the activity of the LIF/STAT3 pathway. The upregulation of Tbx3 by increased activity of the Wnt and LIF/STAT3 pathways promotes the differentiation of both mouse and human ESCs to mesendoderm under the SMG environment. Finally, the ATAC-seq and ChIP-seq analysis in this study reveal a minor effect of SMG on the global chromatin accessibility and the overall patterns of the tested histone modifications in mESCs.