ABSTRACT: Tip5/Baz2a Regulates Chromatin Architecture and Gene Expression to Maintain Self-renewal and Pluripotency of Embryonic Stem Cells [microarray]
Project description:Tip5/Baz2a Regulates Chromatin Architecture and Gene Expression to Maintain Self-renewal and Pluripotency of Embryonic Stem Cells [ChIP-seq]
Project description:It is unclear how gene networks that regulate self-renewal and pluripotency of embryonic stem (ES) cells are established. We searched for factors that contribute to forming functional chromatin architecture in ES cells and identified Tip5 (also called Baz2a) as a genome organizer, folding chromatin and recruiting chromatin remodeling/epigenetic factors to genes. Tip5 binds specialized genomic sequences called base-unpairing regions (BURs) and localizes near heterochromatin. Through chromatin looping Tip5 recruits the polycomb-repressive complex 2 (PRC2) subunits and Jarid2 to target genes far from Tip5-bound BURs and alters their histone profiles. In ES cells Tip5 represses PRC2-bound developmental genes and regulates non-PRC2-bound genes that are enriched for G-protein coupled receptor signaling. Tip5 knockdown caused misexpression of these genes important for ES cell maintenance, leading to rapid ES cell differentiation and impaired pluripotency. These data suggest that Tip5 regulates multiple processes through ES cell-specific genome organization to maintain ES cell stemness.
Project description:It is unclear how gene networks that regulate self-renewal and pluripotency of embryonic stem (ES) cells are established. We searched for factors that contribute to forming functional chromatin architecture in ES cells and identified Tip5 (also called Baz2a) as a genome organizer, folding chromatin and recruiting chromatin remodeling/epigenetic factors to genes. Tip5 binds specialized genomic sequences called base-unpairing regions (BURs) and localizes near heterochromatin. Through chromatin looping Tip5 recruits the polycomb-repressive complex 2 (PRC2) subunits and Jarid2 to target genes far from Tip5-bound BURs and alters their histone profiles. In ES cells Tip5 represses PRC2-bound developmental genes and regulates non-PRC2-bound genes that are enriched for G-protein coupled receptor signaling. Tip5 knockdown caused misexpression of these genes important for ES cell maintenance, leading to rapid ES cell differentiation and impaired pluripotency. These data suggest that Tip5 regulates multiple processes through ES cell-specific genome organization to maintain ES cell stemness.
Project description:Embryonic stem cell (ESC) self-renewal and pluripotency is controlled by the coordinated action of transcription factors and chromatin regulators. Compared to the pluripotency transcription factors, the function of the chromatin regulators, especially the ATP-dependent chromatin remodelers, remains poorly understood in ESCs. Here, we show that INO80, a SWI/SNF family chromatin remodeling complex, is essential for ESC self-renewal, pluripotency, somatic cell reprogramming, and embryonic development. Ino80, the ATPase of the complex, forms an auto-regulatory loop with the ESC master transcription factors Oct4, Nanog, and Sox2. More importantly, it co-occupies the enhancer regions of most key pluripotency genes with the master transcription factors, and positively regulates their expression by maintaining an open chromatin structure. Our data suggests that INO80 is an integral component of the pluripotency transcription network, and plays a critical role in both the maintenance and establishment of pluripotency Identification of Ino80 localization in mouse embryonic stem cells
Project description:Oct4 is considered a master transcription factor for pluripotent cell self-renewal and embryo development. It primarily collaborates with other transcriptional factors or coregulators to maintain pluripotency. However, it is still unclear how Oct4 interacts with its partners. Here, we show that the Oct4 linker interface mediates competing and balanced Oct4 protein interactions which are crucial for maintaining pluripotency. Linker mutant ESCs maintain the key pluripotency genes expression, but show decreased expression of self-renewal genes and increased expression of differentiation genes which result in impaired ESCs self-renewal and early embryonic lethality. Linker mutation dose not affect Oct4 genomic binding and transactivation potential, but breaks the balanced Oct4 interactome. In mutant ESCs, the interaction between Oct4 and Klf5 was decreased, but interactions between Oct4 and Cbx1, Ctr9, Cdc73 were increased which disrupt the epigenetic state of ESCs. Overexpression of Klf5 or knockdown Cbx1, Cdc73 rescue the cellular phenotype of linker mutant ESCs by rebalancing Oct4 interactome indicating that different partners interact with Oct4 competitively. Thus, by showing how Oct4 interacts with different partners, we provide novel molecular insights to explain how Oct4 contributes to the maintenance of pluripotency.
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:O-linked-N-acetylglucosamine (O-GlcNAc) has emerged as a critical regulator of diverse cellular processes, but its role in embryonic stem cells (ESCs) and pluripotency has not been investigated. Here we show that O-GlcNAcylation directly regulates core components of the pluripotency network. Blocking O-GlcNAcylation disrupts ESC self-renewal and reprogramming of somatic cells to induced pluripotent stem cells. The core reprogramming factors Oct4 and Sox2 are O-GlcNAcylated in ESCs, but the O-GlcNAc modification is rapidly removed upon differentiation. O-GlcNAc modification of Threonine 228 in Oct4 regulates Oct4 transcriptional activity and is important for inducing many pluripotency related genes, including Klf2, Klf5, Nr5a2, Tbx3 and Tcl1. A T228A point mutation that eliminates this O-GlcNAc modification reduces the capacity of Oct4 to maintain ESC self-renewal and reprogram somatic cells. Overall, our study makes a direct connection between O-GlcNAcylation of key regulatory transcription factors and the activity of the pluripotency network. 2 of E14 stem cell, 2 of embryonic body at day 2, 2 of embryonic body at day 2 treated with streptozotocin, 1 of ZHBTc4 stem cell treated with doxicyclin, and 1 of ZHBTc4 stem cell treated with doxicyclin and streptozotocin were analysed
Project description:Embryonic stem cell (ESC) self-renewal and pluripotency is controlled by the coordinated action of transcription factors and chromatin regulators. Compared to the pluripotency transcription factors, the function of the chromatin regulators, especially the ATP-dependent chromatin remodelers, remains poorly understood in ESCs. Here, we show that INO80, a SWI/SNF family chromatin remodeling complex, is essential for ESC self-renewal, pluripotency, somatic cell reprogramming, and embryonic development. Ino80, the ATPase of the complex, forms an auto-regulatory loop with the ESC master transcription factors Oct4, Nanog, and Sox2. More importantly, it co-occupies the enhancer regions of most key pluripotency genes with the master transcription factors, and positively regulates their expression by maintaining an open chromatin structure. Our data suggests that INO80 is an integral component of the pluripotency transcription network, and plays a critical role in both the maintenance and establishment of pluripotency
Project description:Embryonic stem cell (ESC) self-renewal and pluripotency is controlled by the coordinated action of transcription factors and chromatin regulators. Compared to the pluripotency transcription factors, the function of the chromatin regulators, especially the ATP-dependent chromatin remodelers, remains poorly understood in ESCs. Here, we show that INO80, a SWI/SNF family chromatin remodeling complex, is essential for ESC self-renewal, pluripotency, somatic cell reprogramming, and embryonic development. Ino80, the ATPase of the complex, forms an auto-regulatory loop with the ESC master transcription factors Oct4, Nanog, and Sox2. More importantly, it co-occupies the enhancer regions of most key pluripotency genes with the master transcription factors, and positively regulates their expression by maintaining an open chromatin structure. Our data suggests that INO80 is an integral component of the pluripotency transcription network, and plays a critical role in both the maintenance and establishment of pluripotency