Project description:The two vertebrate Gsk-3 isoforms, Gsk-3a and Gsk-3b, are encoded by distinct genetic loci and exhibit mostly redundant function in murine embryonic stem cells (ESCs). Here we report that deletion of both Gsk-3a and Gsk-3b in mouse ESCs results in significant changes in gene expression. In contrast, deletion of either Gsk-3a or Gsk-3b individually had little effect on gene expression. These data support the notion that Gsk-3 isoforms are functionally redundant in embryonic stem cells. In addition, we did not find the expected upregulation of known Wnt target genes. Our data suggests that Gsk-3-meidated regulation of gene expression in embryonic stem cells is complex, and likely involves affects on numerous signaling pathways. The study was designed to examine the changes in gene expression between wild-type, Gsk-3a-/-, Gsk-3b-/-, and Gsk-3a-/-;Gsk-3b-/- mouse embryonic stem cells.
Project description:DNA methylation plays a critical role in development, particularly in repressing retrotransposons. The mammalian methylation landscape is dependent on the combined activities of the canonical maintenance enzyme Dnmt1 and the de novo Dnmts, 3a and 3b. Here we demonstrate that Dnmt1 displays de novo methylation activity in vitro and in vivo with specific retrotransposon targeting. We used whole-genome bisulfite and long-read Nanopore sequencing in genetically engineered methylation depleted embryonic stem cells to provide an in-depth assessment and quantification of this activity. Utilizing additional knockout lines and molecular characterization, we show that Dnmt1's de novo methylation activity depends on Uhrf1 and its genomic recruitment overlaps with targets that enrich for Trim28 and H3K9 trimethylation. Our data demonstrate that Dnmt1 can de novo add and maintain DNA methylation, especially at retrotransposons and that this mechanism may provide additional stability for long-term repression and epigenetic propagation throughout development.
Project description:We generated WGBS datasets from mESCs treated with the novel drug GSK-3484862 attained from two different commercial sources or the conventional DNMT1 inhitibitor 5-azacytidine. To assess efficacy, datasets were generated from mESCs treated with GSK-3484862 at two concentrations and after treatment for 6 days and 14 days each. Additionally, for comparison purposes, we generated WGBS datasets from Dnmt1/3a/3b deficient mESCs which have very low levels of DNA methylation and WT mESCs treated with DMSO which retain high levels of DNA methylation.
Project description:DNMT1 plays a major role in embryonic development as a maintenance methyltransferase. Although recent studies have shown that DNMT1 has de novo methylation activity, the detailed role of its function during embryonic development remains unclear. In this study, to further understand the role of DNMT1 de novo methylation, we performed RNA-seq on DNMT1/3A/3B triple knockout (TKO) mESCs and TKO mESCs expressing DNMT1 (TKO_FL).
Project description:Nephron number is a major determinant of long-term renal function. We hypothesized a link between epigenetic regulation and nephron formation. In support of this hypothesis, expression analysis evidenced high levels of DNA methyltransferases Dnmt1 and Dnmt3a in the nephrogenic zone of the developing mouse kidney. Using targeted loss-of-function manipulations in mice, we show that deletion of Dnmt1 in nephron progenitor cells results in a marked hypoplasia and reduction of nephron number at birth. In contrast, deletion of Dnmt3a/3b in nephron progenitor cells or deletion of Dnmt1/3a/3b in differentiated renal cells did not lead to any overt kidney phenotype. Whole mount optical projection tomography and 3D-reconstructions uncovered a significant reduction of stem cell niches and progenitor cells in Dnmt1-deficient mice. Ultimately, RNA sequencing analysis revealed that Dnmt1 controls DNA transcription regulating progenitor renewal, identity and differentiation. In summary, this study establishes DNA methylation as key regulatory event of prenatal renal programming.
Project description:The two vertebrate Gsk-3 isoforms, Gsk-3a and Gsk-3b, are encoded by distinct genetic loci and exhibit mostly redundant function in murine embryonic stem cells (ESCs). Here we report that deletion of both Gsk-3a and Gsk-3b in mouse ESCs results in significant changes in gene expression. In contrast, deletion of either Gsk-3a or Gsk-3b individually had little effect on gene expression. These data support the notion that Gsk-3 isoforms are functionally redundant in embryonic stem cells. In addition, we did not find the expected upregulation of known Wnt target genes. Our data suggests that Gsk-3-meidated regulation of gene expression in embryonic stem cells is complex, and likely involves affects on numerous signaling pathways.
Project description:Here, we first establish an easy Multi-Stop system to simultaneously inactivate genes involved in DNA methylation and demethylation in zygotes through introduction of the stop codon by hA3A-eBE-Y130F-mediated base editor (BE). While Multi-Stop-derived Dnmt-null embryos display embryonic lethal due to gastrulation failure. Moreover, mutation combinations between Tet and Dnmt families show severe embryonic lethal and Dnmt1 or Dnmt3a/3b is indispensable for mouse gastrulation. Then WGBS and RNA-seq analysis of different mutant embryos reveals genes jointly maintained by Dnmt1 and Dnmt3a/3b that are critical for gastrulation.