Ectopic expression of DNA methyltransferases DNMT3A2 and DNMT3L leads to aberrant hypermethylation and postnatal lethality in mice
Ontology highlight
ABSTRACT: DNA methylation is generally known to inactivate gene expression. The DNA methyltransferases (DNMTs), DNMT3A and DNMT3B, catalyze somatic cell lineage-specific DNA methylation, while DNMT3A and DNMT3L catalyze germ cell lineage-specific DNA methylation. How such lineage- and gene-specific DNA methylation patterns are created remains to be elucidated. To better understand the regulatory mechanisms underlying DNA methylation, we generated transgenic mice that constitutively expressed DNMT3A and DNMT3L, and analyzed DNA methylation, gene expression, and their subsequent impact on ontogeny. All transgenic mice were born normally but died within 20 weeks accompanied with cardiac hypertrophy. Several genes were repressed in the hearts of transgenic mice compared with those in wild-type mice. CpG islands of these downregulated genes were highly methylated in the transgenic mice. This abnormal methylation occurred in the perinatal stage. Conversely, mono-allelic DNA methylation at imprinted loci was faithfully maintained in all transgenic mice, except H19. Thus, the loci preferred by DNMT3A and DNMT3L differ between somatic and germ cell lineages.
Project description:DNA methyltransferase 3A (DNMT3A) and DNA methyltransferase 3-Like (DNMT3L) form functional heterotetramers and ATRX-DNMT3-DNMT3L (ADD) domains, shared by both DNMT3A and DNMT3L, recognizes histone H3 tail unmethylated at lysine-4 (H3K4me0) to deposit DNA methylation properly in mammalian germ cells. However, the combinational and differential role of ADD domains of DNMT3A and DNMT3L in vivo has not been fully defined. Here we analyze both female and male germ cells derived from mouse with amino-acid substitutions in ADD domains of DNMT3A and/or DNMT3L that impair their domain function. Loss of either DNMT3A-ADD or DNMT3L-ADD domain function shows moderate reduction of global CG methylation level, but in different degree, in both germ cells. However, when both DNMT3A and DNMT3L lost their ADD domain functions, reduction of the global CG methylation level is much more severe and comparable with that of Dnmt3a/3L knockout germ cells. In contrast, such double mutant germ cells have thousands of genomic regions where non-CG methylation is aberrantly accumulated. These results highlight a critical role of the combinational function of ADD domains for the robust CG and non-CG methylation in germ cells.
Project description:DNA methyltransferase 3A (DNMT3A) and DNA methyltransferase 3-Like (DNMT3L) form functional heterotetramers and ATRX-DNMT3-DNMT3L (ADD) domains, shared by both DNMT3A and DNMT3L, recognizes histone H3 tail unmethylated at lysine-4 (H3K4me0) to deposit DNA methylation properly in mammalian germ cells. However, the combinational and differential role of ADD domains of DNMT3A and DNMT3L in vivo has not been fully defined. Here we analyze both female and male germ cells derived from mouse with amino-acid substitutions in ADD domains of DNMT3A and/or DNMT3L that impair their domain function. Loss of either DNMT3A-ADD or DNMT3L-ADD domain function shows moderate reduction of global CG methylation level, but in different degree, in both germ cells. However, when both DNMT3A and DNMT3L lost their ADD domain functions, reduction of the global CG methylation level is much more severe and comparable with that of Dnmt3a/3L knockout germ cells. In contrast, such double mutant germ cells have thousands of genomic regions where non-CG methylation is aberrantly accumulated. These results highlight a critical role of the combinational function of ADD domains for the robust CG and non-CG methylation in germ cells.
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: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 methyltransferases 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 Ezh2 ChIP-Seq in shGFP and shDnmt3L ESC. Examination of Dnmt3L ChIP-Seq in shGFP and shSuz12 ESC.
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. Total RNA extracted from shGFP or shDnmt3L (three different) embryonic stem cells. A duplicate was performed for each point. Cells were transfected with shRNA and selected with Puromicin for 3 days before RNA extraction
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 methyltransferases 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.
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.
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.
Project description:We used RRBS to analyze DNA methylation in mESC lines deficient for maternal Dnmt3L (Dnmt3L mKO), zygotic Dnmt3L (Dnmt3L KO), and both maternal and zygotic Dnmt3L (Dnmt3L mzKO). Compared to wild-type (WT) mESCs, Dnmt3L mKO mESCs exhibit severe loss of methylation at imprinted loci but no changes in global DNA methylation, Dnmt3L KO mESCs exhibit moderate loss of methylation at many Dnmt3a target regions but do not affect methylation at imprinted loci, and Dnmt3L mzKO mESCs exhibit combined changes of mKO and KO cells, with severe loss of methylation at imprinted loci and moderate loss of methylation at Dnmt3a target regions.
Project description:During early mammalian development, DNA methylation undergoes two waves of reprogramming, enabling transitions between somatic cells, oocyte and embryo. The first wave of de novo DNA methylation establishment occurs in the oocytes. Its molecular mechanisms has been studied in mouse, a classical mammalian model. Current dogma describes DNA methyltransferase 3A (DNMT3A) and its cofactor DNMT3L as two essential factors for oocyte DNA methylation – the ablation of either leads to nearly complete abrogation of DNA methylation. However, DNMT3L is not expressed in human oocytes, suggesting that the mechanism uncovered in mouse is not universal across mammals. We analyzed available RNA-seq datasets from oocytes of multiple mammals including our novel naked mole-rat oocytes dataset, and revealed that Dnmt3l is expressed only in the oocytes of mouse, rat and golden hamster. We identified a specific promoter sequence recognised by an oocyte transcription factor complex associated with Dnmt3l activity and demonstrated that it emerged in the rodent clade Eumuroida, comprising the families Muridae (mice, rats, gerbils) and Cricetidae (hamsters). Therefore, Dnmt3l is expressed and consequently plays a role in de novo DNA methylation only in the oocytes of these species, instead of being an essential pan-mammalian factor.