Project description:The pluripotency-associated transcriptional network is regulated by a core circuitry of transcription factors. The PR domain-containing protein, PRDM14, maintains pluripotency by activating and repressing transcription in a target gene-dependent manner. However, the mechanisms underlying dichotomic switching of PRDM14-mediated transcriptional control remains elusive. Here, we identified C-terminal binding protein 1/2 (CtBP1/2) as components of the PRDM14-mediated repressive complex. CtBP1/2 binding to PRDM14 depends on CBFA2T2, a core component of the PRDM14 complex. The loss of Ctbp1/2 impaired the PRDM14-mediated transcriptional repression required for pluripotency maintenance and primed to naïve pluripotency transition. Furthermore, CtBP1/2 also interacted with the PRC2 complexes, and the loss of Ctbp1/2 impaired the PRC2 and H3K27me3 enrichment at the target genes upon PRDM14 overexpression. These results suggest that evidence that the target gene-dependent transcriptional activity of PRDM14 is regulated by partner switching to ensure transition from primed to naïve pluripotency.
Project description:Gene regulatory networks underlying cellular pluripotency are controlled by a core circuitry of transcription factors, including POU5F1 and NANOG in mammals. However, the evolutionary origin and transformation of pluripotency transcriptional networks have not been elucidated in deuterostomes. PR domain-containing protein 14 (PRDM14) is specifically expressed in pluripotent cells and germ cells, and is required for establishing embryonic stem cells (ESCs) and primordial germ cells (PGCs) in mice. Here, we compared the functions and expression patterns of PRDM14 orthologues within deuterostomes. Amphioxus PRDM14, zebrafish PRDM14, and the combination of sea urchin PRDM14 and CBFA2T compensated for disruption of the mouse Prdm14 gene in terms of maintaining mouse ESC pluripotency. Interestingly, Prdm14 was expressed in motor neurons, but not in germ cells in amphioxus embryos as observed in zebrafish embryos. Therefore, our results suggest that the integration of the PRDM14–CBFA2T complex into the transcriptional network for pluripotency may be essential for stabilizing pluripotency during the early amniote development.
Project description:Germline cells reprogram extensive epigenetic modifications to ensure the cellular totipotency of the next generation and prevent accumulation of epimutations. Primordial germ cells (PGCs)1, the common source of both oocytes and sperm, erase genome-wide DNA methylation and histone H3 lysine 9 dimethylation (H3K9me2), a process called genome-wide epigenetic reprogramming2,3. However, little is known about the molecular mechanism of DNA demethylation by developing PGCs. Here we show that overexpression of PRDM14, a critical regulator for specification and early differentiation of PGCs, promotes global DNA demethylation in embryonic stem cells (ESCs). PRDM14 directly represses transcription of de novo DNA methyltransferase, Dnmt3b, but its repression is not sufficient for global DNA demethylation. Comparison of global gene expression profiles between PRDM14-overexpressing ESCs and Dnmts triple mutant ESCs clearly demonstrates that overexpression of PRDM14 activates about half of the genes silenced by DNA methylation in ESCs. Furthermore, PRDM14 directly interacts with TET1, which converts 5-methylcytosine to 5-hydroxymethylcytosine, and DNA demethylation by overexpression of PRDM14 is strongly disturbed by pharmacological inhibitors of the base excision repair (BER) pathway. We propose that formation of a PRDM14/TET1 complex triggers the activation of BER-dependent active demethylation across the whole genome of developing PGCs.
Project description:Suz12(Bgal/Bgal) ESCs express a truncated form of Suz12 fused to Beta-galactosidase. These cells maintain a reduced level of H3K27me3 despite this mutation to a core component of PRC2, unlike Eed-/- ESCs whose H3K27me3 is ablated. RNA-seq was performed in wild type and Suz12(Bgal/Bgal) ESCs, here used to demonstrate the coverage of the Suz12 gene in mRNA reads.
Project description:Suz12 exon 4 encodes 23 amino acids (aa 129–152 in SUZ12-L) that partially overlap with the WD-binding domain 1 (WDB1, 110–145). We reasoned that exon 4 skipping might alter the structure of SUZ12 and, possibly, PRC2 composition. To explore this possibility, we generated ESCs that lack the Suz12 exon 4 via CRISPR-Cas9–induced deletion. In addition, to rule out any biases due to the expression levels and/or SUZ12 epitope masking, we generated Suz12 knockout (KO) ESCs (herein, KO) in which Suz12 expression was subsequently rescued by re-introducing either the Suz12-L or Suz12-S mouse isoform fused to a triple-Flag tag under the regulation of a CAG promoter (KO+L/S; Figures S2H–S2K). We performed SUZ12 immunoprecipitation coupled with mass spectrometry (IP-MS) in the WT and ∆ex4 clones to compare their interactomes and with a flag antibody in the KO and rescue cell lines. As expected, no peptides corresponding to exon 4 were retrieved in ∆ex4 samples, while the rest of the sequence displayed similar coverage. Comparison of interactors in the two conditions revealed that SUZ12 binding to AEBP2 and JARID2 was strongly reduced in ∆ex4 cells with respect to WT cells, whereas SUZ12 binding to most core components or to PRC2.1-specific factors was unchanged or only slightly increased . These observations were confirmed by SUZ12 IP followed by Western blot (WB). Flag IP-MS in rescue cells confirmed that, while the long isoform was able to correctly form comparable amounts of both PRC2.1 and PRC2.2 subtypes, interaction of the SUZ12-S with PRC2.2-specific factors was drastically reduced.
Project description:Suz12(Bgal/Bgal) ESCs express a truncated form of Suz12 fused to Beta-galactosidase. These cells maintain a reduced level of H3K27me3 despite this mutation to a core component of PRC2, unlike Eed-/- ESCs whose H3K27me3 is ablated.
Project description:Suz12(Bgal/Bgal) ESCs express a truncated form of Suz12 fused to Beta-galactosidase. These cells maintain a reduced level of H3K27me3 despite this mutation to a core component of PRC2, unlike Eed-/- ESCs whose H3K27me3 is ablated.
Project description:Purpose:The goals of this study is to analyze the gene expession pattern in mouse embryonic stem cells (ESCs) ovexpressed flag or mouse flag tagged Prdm14
Project description:Suz12(Bgal/Bgal) ESCs express a truncated form of Suz12 fused to Beta-galactosidase. These cells maintain a reduced level of H3K27me3 despite this mutation to a core component of PRC2, unlike Eed-/- ESCs whose H3K27me3 is ablated. This data shows the concomitant changes in H3K4me3 levels in these cells.