Project description:Prdm14 is a PR-domain and zinc-finger protein whose expression is restricted to the pluripotent cells of an early embryo, embryonic stem cells (ESCs), and germ cells. Here we show that Prdm14 safeguards mouse ESC maintenance by preventing induction of extraembryonic endoderm (ExEn) fates. Conversely, Prdm14 overexpression impairs ExEn differentiation during embryoid body (EB) formation. Prdm14 occupies and represses genomic loci encoding ExEn differentiation factors, while also binding to and promoting expression of genes associated with ESC self-renewal. Prdm14-bound genomic regions significantly overlap those occupied by Nanog and Oct4, are enriched in a chromatin signature associated with distal regulatory elements, and contain a unique DNA-sequence motif recognized by Prdm14 in vitro. Our work identifies Prdm14 as a new member of mouse ESC (mESC) transcriptional network, which plays a dual role as a context-dependent transcriptional repressor or activator at distal silencers and enhancers. [ChIP-seq] Genome-wide mapping of Prdm14 binding sites in mouse embryonic stem cells: A FLAG-HA tagged Prdm14 (FH-Prdm14) mESC line was established. FLAG-HA double ChIP (ChIP with FLAG antibody followed by ChIP with HA antibody) was performed with FH-Prdm14 mESCs (Prdm14-ChIPseq) and as a negative control, wildtype mESCs (FLAG-HA_ChIPseq). H3K4me1 ChIPseq in mouse ES cells. Using published H3K4me1 data, we found there is a correlation between Prdm14 binding and H3K4me1 marks. So we obtained our own H3K4me1 data, using the wildtype mESCs. [RNA-seq] Global RNAseq analysis of Prdm14 knockdown in mouse embryonic stem cells: Analysis of poly(A)+ RNA from mESCs treated with non-targeting control siRNA and Prdm14 siRNA.
Project description:Prdm14 is a sequence-specific transcriptional regulator of embryonic stem cell (ESC) pluripotency and primordial germ cell (PGC) formation. It exerts its function, at least in part, through repressing genes associated with epigenetic modification and cell differentiation. Here, we show that this repressive function is mediated through an ETO-family co-repressor Mtgr1, which tightly binds to the pre-SET/SET domains of Prdm14 and co-occupies its genomic targets in mouse ESCs. Structure-guided point mutants abrogated the Prdm14-Mtgr1 association and disrupted Prdm14's function in mESC gene expression and PGC formation in vitro. Altogether, our work uncovers the molecular mechanism underlying Prdm14-mediated repression. Examination of Prdm14 and Mtgr1 occupancy by ChIP-seq and effects on gene expression in mouse embryonic stem cells
Project description:PRDM14 is a crucial regulator of mouse primordial germ cells (mPGC), epigenetic reprogramming and pluripotency, but its role in the evolutionarily divergent regulatory network of human PGCs (hPGCs) remains unclear. Besides, a previous knockdown study indicated that PRDM14 might be dispensable for human germ cell fate. Here, we decided to use inducible degrons for a more rapid and comprehensive PRDM14 depletion. We show that PRDM14 loss results in significantly reduced specification efficiency and an aberrant transcriptome of human PGC-like cells (hPGCLCs) obtained in vitro from human embryonic stem cells (hESCs). Chromatin immunoprecipitation and transcriptomic analyses suggest that PRDM14 cooperates with TFAP2C and BLIMP1 to upregulate germ cell and pluripotency genes, while repressing WNT signalling and somatic markers. Notably, PRDM14 targets are not conserved between mouse and human, emphasising the divergent molecular mechanisms of PGC specification. The effectiveness of degrons for acute protein depletion is widely applicable in various developmental contexts.
Project description:PRDM14 is a crucial regulator of mouse primordial germ cells (mPGC), epigenetic reprogramming and pluripotency, but its role in the evolutionarily divergent regulatory network of human PGCs (hPGCs) remains unclear. Besides, a previous knockdown study indicated that PRDM14 might be dispensable for human germ cell fate. Here, we decided to use inducible degrons for a more rapid and comprehensive PRDM14 depletion. We show that PRDM14 loss results in significantly reduced specification efficiency and an aberrant transcriptome of human PGC-like cells (hPGCLCs) obtained in vitro from human embryonic stem cells (hESCs). Chromatin immunoprecipitation and transcriptomic analyses suggest that PRDM14 cooperates with TFAP2C and BLIMP1 to upregulate germ cell and pluripotency genes, while repressing WNT signalling and somatic markers. Notably, PRDM14 targets are not conserved between mouse and human, emphasising the divergent molecular mechanisms of PGC specification. The effectiveness of degrons for acute protein depletion is widely applicable in various developmental contexts.
Project description:Analysis of Prdm14 function in mouse embryonic stem cells. Prdm14 null and overexpressing ES cells were generated and analyzed by microarray, immunoflurescence, flow cytometry, ELISA, qPCR in different culture conditions.
Project description:Analysis of Prdm14 function in mouse embryonic stem cells. Prdm14 null and overexpressing ES cells were generated and analyzed by microarray, immunoflurescence, flow cytometry, ELISA, qPCR in different culture conditions.
Project description:During development, transcriptional and chromatin modification changes co-occur but the order and causality of events often remain unclear. We explore the interrelationship of these processes using the paradigm of X-chromosome inactivation (XCI). We initiate XCI in female, mouse embryonic stem cells by inducing Xist expression and monitor changes in transcription and chromatin by allele-specific TT-seq and ChIP-seq respectively. An unprecedented temporal resolution enabled identification of the earliest chromatin alterations during XCI. We demonstrate that HDAC3 interacts with both NCOR1 and NCOR2 and is pre-bound on the X chromosome where it deacetylates histones to promote efficient gene silencing. We also reveal the choreography of polycomb accumulation following Xist RNA coating, with PRC1-associated H2AK119Ub preceding PRC2-associated H3K27me3. Furthermore, polycomb-associated marks accumulate initially at large, intergenic domains and then spreads into genes but only in the context of gene silencing. Our results provide the hierarchy of chromatin events during XCI and demonstrate that some chromatin changes play key roles in mediating transcriptional silencing.
Project description:Scaffold Attachment Factor B (SAFB) is a conserved RNA Binding Protein (RBP) that is essential for early mammalian development. However, the RNAs that associate with SAFB in mouse embryonic stem cells have not been characterized. Here, we addressed this unknown using RNA-seq and SAFB RNA immunoprecipitation followed by RNA-seq (RIP-seq) in wild-type mouse embryonic stem cells (ESCs) and in ESCs in which SAFB and SAFB2 were knocked out. The transcript most enriched in SAFB association was the lncRNA Malat1, which contains a series of purine-rich motifs in its 5 end. Beyond Malat1, SAFB predominantly associated with introns of protein-coding genes also through purine-rich motifs. Knockout of SAFB/2 led to down- and upregulation of genes in multiple biological pathways. The nascent transcripts of many downregulated genes associated with high levels of SAFB in wild-type cells, implying that SAFB binding promotes the expression of these genes. Reintroduction of SAFB into double-knockout cells restored gene expression towards wild-type levels, an effect that was again observable at the level of nascent transcripts. Proteomic analyses indicate an enrichment of nuclear speckle-associated, SR proteins in FLAG-tagged SAFB immunoprecipitated samples. Comparison to immunoprecipitates made from FLAG-tagging of another nuclear-enriched RNA-binding protein called HNRNPU (also known as SAF-A) identified both similarities and differences. Perhaps most notably, we observed a stronger enrichment for speckle-associated proteins in SAFB immunoprecipitations and a strong enrichment for paraspeckle-associated proteins in HNRNPU immunoprecipitations. Our findings suggest that among other potential functions in mouse embryonic stem cells, SAFB directly promotes the expression of a subset of genes through its ability to bind purine regions in nascent RNA.
Project description:Prdm14 is a PR-domain and zinc-finger protein whose expression is restricted to the pluripotent cells of an early embryo, embryonic stem cells (ESCs), and germ cells. Here we show that Prdm14 safeguards mouse ESC maintenance by preventing induction of extraembryonic endoderm (ExEn) fates. Conversely, Prdm14 overexpression impairs ExEn differentiation during embryoid body (EB) formation. Prdm14 occupies and represses genomic loci encoding ExEn differentiation factors, while also binding to and promoting expression of genes associated with ESC self-renewal. Prdm14-bound genomic regions significantly overlap those occupied by Nanog and Oct4, are enriched in a chromatin signature associated with distal regulatory elements, and contain a unique DNA-sequence motif recognized by Prdm14 in vitro. Our work identifies Prdm14 as a new member of mouse ESC (mESC) transcriptional network, which plays a dual role as a context-dependent transcriptional repressor or activator at distal silencers and enhancers.