Project description:The de novo DNA methyltransferase 3-like (Dnmt3L) is a catalytically inactive DNA methylase that has been previously shown to cooperate with Dnmt3a and Dnmt3b to methylate DNA. Dnmt3L is highly expressed in mouse embryonic stem cells (ESC) but its function in these cells is unknown. We here report that Dnmt3L is required for the differentiation of ESC into primordial germ cells (PGC) through activation of the homeotic gene Rhox5. By genome-wide analysis we found that Dnmt3L is a positive regulator of methylation at gene bodies of housekeeping genes and a negative regulator of methylation at promoters of bivalent genes. We demonstrate that Dnmt3L interacts with the Polycomb PRC2 complex in competition with the DNA methyl transferases Dnmt3a and Dnmt3b to maintain low the methylation level at H3H27me3 regions. Thus in ESC, Dnmt3L counteracts the activity of de novo DNA methylases to keep low the level of DNA methylation at developmental gene promoters. Examination of 5mC in shGFP and shDnmt3L ESC by MeDIP-Seq
Project description:Genomewide DNA methylation profiles, generated by MeDIP-seq, for 8.5dpc wildtype and Dnmt3l-/+ mouse embryos were compared to identify differentially methylated regions (DMRs) that depend on the activity of the de novo DNA methyltransferase cofactor Dnmt3l in the oocyte. These DMRs were further characterised by their methylation state in mature mouse sperm and in the livers of inter-subspecies newborn mice. Maternal ICRs were identified by hypomethylation in Dnmt3l-/+ embryos as well as sperm, and maternal allele-specific methylation in liver. MeDIP-seq for two pools of wildtype and two pools of Dnmt3l-/+ mouse 8.5dpc embryos, the sperm of three sires, and 12 pools of three different embryonic livers each. Sliding window read count comparison between wildtype and Dnmt3l-/+ embryos, and between wildtype embryos and sperm samples. Read count comparison between the parental alleles at known SNP sites in inter-subspecies liver data.
Project description:Ligation of the B cell antigen receptor (BCR) initiates humoral immunity. However, mere BCR signaling without appropriate co-stimulation commits B cells to death rather than to differentiation into immune effector cells. How BCR activation depletes potentially autoreactive B cells while simultaneously primes for receiving rescue and differentiation signals from cognate T lymphocytes remains unknown. Here, using a mass spectrometry-based proteomic approach to identify cytosolic/nuclear shuttling elements, we uncover transcription factor EB (TFEB) as a central BCR-controlled rheostat that drives activation-induced apoptosis, and concurrently, promotes the reception of co-stimulatory rescue signals by supporting B cell migration and antigen presentation. CD40 co-stimulation prevents TFEB-driven cell death, while enhancing and prolonging TFEB’s nuclear residency, which hallmarks antigenic experience also of memory B cells. In mice, TFEB shapes the transcriptional landscape of germinal center B cells. Within the germinal center, TFEB facilitates the dark zone entry of light-zone-residing centrocytes through regulation of chemokine receptors and, by balancing the expression of Bcl-2/BH3-only family members, integrates antigen-induced apoptosis with T cell-provided CD40 survival signals. Thus, TFEB reprograms antigen-primed germinal center B cells for cell fate decisions.
Project description:Genomewide DNA methylation profiles, generated by MeDIP-seq, for 8.5dpc wildtype and Dnmt3l-/+ mouse embryos were compared to identify differentially methylated regions (DMRs) that depend on the activity of the de novo DNA methyltransferase cofactor Dnmt3l in the oocyte. These DMRs were further characterised by their methylation state in mature mouse sperm and in the livers of inter-subspecies newborn mice. Maternal ICRs were identified by hypomethylation in Dnmt3l-/+ embryos as well as sperm, and maternal allele-specific methylation in liver.
Project description:DNA methylation is essential for mammalian development. Studies of the catalytically inactive DNA methyltransferase Dnmt3l have mainly been limited to mice where Dnmt3l was shown to be essential for fertility, de novo DNA methylation in early embryos and maintenance of DNA methylation patterns in mouse pluripotent stem cells. Recent work revealed that DNMT3L is the most highly enriched chromatin factor in naive human pluripotent stem cells (hPSCs) compared with primed hPSCs. Stem cell-based human embryo models and naive hPSCs provide a unique opportunity to functionally dissect human developmental mechanisms. Here we use naive hPSCs and human blastoids, a 3D human blastocyst model, to investigate the functional impact of DNMT3L on human naive pluripotency and preimplantation development. We demonstrate an essential role of DNMT3L in trophectoderm cell fate induction, maintenance of DNA methylation patterns and chromatin states in naive hPSCs, and blastoid lineage identity. We further show that DNMT3L promotes reprogramming to naive pluripotency, and has integrated a hominoid-specific naive human pluripotency gene regulatory program involving evolutionary recent transposable elements. Therefore, DNMT3L plays conserved and hominoid-specific functions in human naive pluripotency and pre-implantation development.
Project description:The roles of translational control in the immune system are poorly understood. In this study, we performed CRISPR/Cas9-mediated functional screening of RNA helicases in an in vitro system of plasma cell differentiation and identified Dhx29 as a critical regulator of this process. Mice with B cell-specific deletion of Dhx29 exhibited severely impaired germinal center B cell formation, plasma cell differentiation, and antibody production. Mechanistically, Dhx29 promotes translation of Tcf3 and Tle3 via binding to 5’UTRs of those mRNAs. In the absence of Dhx29, B cells exhibit normal proliferation but fail to undergo class switch to IgG1 and differentiation into plasma cells, resulting in impaired antibody production. Ectopic expression of TCF3 and Tle3 largely restores plasma cell differentiation of Dhx29-deficient B cells. Therefore, this study unravels critical roles of Dhx29 in promoting translation of key transcription factors controlling germinal center response and plasma cell differentiation, discovers a previously unrecognized role of Tle3 in plasma cell differentiation, and illustrates the functional importance of translation control in the immune system.
Project description:Serum response factor (SRF) is a transcription factor essential for cell proliferation, differentiation, and migration, and is required for primitive streak and mesoderm formation in the embryo. The canonical roles of SRF are mediated by a diverse set of context-dependent cofactors. Here we show that SRF physically interacts with CTCF and cohesin subunits at TAD boundaries and loop anchors. SRF reinforces the insulation of TADs and promotes the formation of long-range chromatin loops. In ES cells, SRF associates with Oct4, Sox2, and Nanog and contributes to the formation of 3D pluripotency hubs. Our findings reveal new roles of SRF in higher-order chromatin organization.