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: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.
Project description:Klhl6 belongs to the KLHL gene family, which is composed of an N-terminal BTB-POZ domain and 4 to 6 Kelch motifs in tandem. Several of these proteins function as adaptors of the Cullin3 E3 ubiquitin ligase complex. Here we report that Klhl6 deficiency induces, as previously described, a two-fold reduction in mature B cells. However, we find that this deficit is centered on the inability of transitional T1 B cells to survive and to progress toward the T2 B cell stage, whereas cells that have passed this step generate normal germinal centers upon a T-dependent immune challenge. Klhl6-deficient T1 B cells showed a two-fold over-expression of genes linked with cell proliferation, including most targets of the APC/C complex, a set of genes whose expression is precisely down-modulated upon culture of splenic transitional B cells in presence of BAFF. These results thus suggest a delay in the differentiation process of Klhl6-deficient B cells between the immature and transitional stage. We further show, in the BL2 Burkitt’s lymphoma cell line, that KLHL6 interacts with Cullin3, but also that it binds to HBXIP/Lamtor5, a protein involved in cell cycle regulation and cytokinesis. Finally, we report that KLHL6, which is recurrently mutated in B cell lymphomas, is an off-target of the normal somatic hypermutation process taking place in germinal center B cells in both mice and humans, thus leaving open, whether, in spite of the lack of impact of Klhl6 deficiency on germinal center B cell expansion, mutants could contribute to the oncogenic process.