Similar Datasets
Project description:CpG methylation by the de novo DNA methyltransferases (DNMTs) 3A and 3B is essential for mammalian development and differentiation and is frequently dysregulated in cancer1. These two DNMTs preferentially bind to nucleosomes yet cannot methylate the DNA wrapped around the nucleosome core2, and favor the methylation of linker DNA at positioned nucleosomes3,4. Here we present the cryo-EM structure of a ternary complex of catalytically competent DNMT3A2, the catalytically inactive accessory subunit DNMT3B3, and a nucleosome core particle flanked by linker DNA. The catalytic-like domain of the accessory DNMT3B3 binds the acidic patch of the nucleosome core, which orients the binding of DNMT3A2 to the linker DNA. The steric constraints of this arrangement suggest that nucleosomal DNA must be moved relative to the nucleosome core for de novo methylation to occur.
2020-06-17 | GSE152639 | GEO
Project description:CpG methylation by the de novo DNA methyltransferases (DNMTs) 3A and 3B is essential for mammalian development and differentiation and is frequently dysregulated in cancer1. These two DNMTs preferentially bind to nucleosomes yet cannot methylate the DNA wrapped around the nucleosome core2, and favor the methylation of linker DNA at positioned nucleosomes3,4. Here we present the cryo-EM structure of a ternary complex of catalytically competent DNMT3A2, the catalytically inactive accessory subunit DNMT3B3, and a nucleosome core particle flanked by linker DNA. The catalytic-like domain of the accessory DNMT3B3 binds the acidic patch of the nucleosome core, which orients the binding of DNMT3A2 to the linker DNA. The steric constraints of this arrangement suggest that nucleosomal DNA must be moved relative to the nucleosome core for de novo methylation to occur. CpG methylation by the de novo DNA methyltransferases (DNMTs) 3A and 3B is essential for mammalian development and differentiation and is frequently dysregulated in cancer1. These two DNMTs preferentially bind to nucleosomes yet cannot methylate the DNA wrapped around the nucleosome core2, and favor the methylation of linker DNA at positioned nucleosomes3,4. Here we present the cryo-EM structure of a ternary complex of catalytically competent DNMT3A2, the catalytically inactive accessory subunit DNMT3B3, and a nucleosome core particle flanked by linker DNA. The catalytic-like domain of the accessory DNMT3B3 binds the acidic patch of the nucleosome core, which orients the binding of DNMT3A2 to the linker DNA. The steric constraints of this arrangement suggest that nucleosomal DNA must be moved relative to the nucleosome core for de novo methylation to occur.
2020-06-17 | GSE152541 | GEO
Project description:Structure of DNA methyltransferases DNMT3A/DNMT3B bound to a nucleosome
| PRJNA639947 | ENA
Project description:Structure of DNA methyltransferases DNMT3A/DNMT3B bound to a nucleosome [array]
| PRJNA639609 | ENA
Project description:Structure of DNA methyltransferases DNMT3A/DNMT3B bound to a nucleosome [seq]
| PRJNA639948 | ENA
Project description:For cytosine (C) demethylation of vertebrate DNA, it is known that the TET proteins could convert 5-methyl C (5-mC) to 5-hydroxymethyl C (5-hmC). However, DNA dehydroxymethylase(s), or enzymes able to directly convert 5-hmC to C, have been elusive. We present in vitro evidence that the mammalian de novo DNA methyltransferases DNMT3A and DNMT3B, but not the maintenance enzyme DNMT1, are also redox-dependent DNA dehydroxymethylases. Significantly, intactness of the C methylation catalytic sites of these de novo enzymes is also required for their 5-hmC dehydroxymethylation activity. That DNMT3A and DNMT3B function bidirectionally both as DNA methyltransferases and as dehydroxymethylases raises intriguing and new questions regarding the structural and functional aspects of these enzymes and their regulatory roles in the dynamic modifications of the vertebrate genomes during development, carcinogenesis, and gene regulation.
| S-EPMC3460417 | biostudies-literature
Project description:The putative de novo methyltransferases, Dnmt3a and Dnmt3b, were reported to have weak methyltransferase activity in methylating the 3' long terminal repeat of Moloney murine leukemia virus in vitro. The activity of these enzymes was evaluated in vivo, using a stable episomal system that employs plasmids as targets for DNA methylation in human cells. De novo methylation of a subset of the CpG sites on the stable episomes is detected in human cells overexpressing the murine Dnmt3a or Dnmt3b1 protein. This de novo methylation activity is abolished when the cysteine in the P-C motif, which is the catalytic site of cytosine methyltransferases, is replaced by a serine. The pattern of methylation on the episome is nonrandom, and different regions of the episome are methylated to different extents. Furthermore, Dnmt3a also methylates the sequence methylated by Dnmt3a on the stable episome in the corresponding chromosomal target. Overexpression of human DNMT1 or murine Dnmt3b does not lead to the same pattern or degree of de novo methylation on the episome as overexpression of murine Dnmt3a. This finding suggests that these three enzymes may have different targets or requirements, despite the fact that weak de novo methyltransferase activity has been demonstrated in vitro for all three enzymes. It is also noteworthy that both Dnmt3a and Dnmt3b proteins coat the metaphase chromosomes while displaying a more uniform pattern in the nucleus. This is the first evidence that Dnmt3a and Dnmt3b have de novo methyltransferase function in vivo and the first indication that the Dnmt3a and Dnmt3b proteins may have preferred target sites.
| S-EPMC84905 | biostudies-literature
Project description:DNA methylation is the net result of deposition by DNA methyltransferases (DNMT1, 3A and 3B) and removal by the Ten-Eleven Translocation 1-3 (TET1-3) family of proteins and/or passive loss by replication. The relative contribution of the individual enzymes and pathways is only partially understood. Here we comprehensively analyzed and mathematically simulated the dynamics of DNA de-methylation during the reprogramming of the hypermethylated serum-cultured mouse embryonic stem cells (ESCs) to the hypomethylated 2i-cultured ground state of mESC. We show that DNA demethylation readily occurs in TET[1-/-, 2-/-] ESCs with similar kinetics as their WT littermates. Vitamin C activation of TET causes accelerated and more profound DNA demethylation without markedly affecting reprogramming kinetics. We developed a mathematical model that highly accurately predicts the global level of 5methyl- and 5hydroxymethylcytosine during the transition. Modeling and experimental validation show that the concentration of DNMT3A and DNMT3B determines the steady state level of global DNA methylation and absence of DNMT3A/B even in continued presence of DNMT1 results in gradual loss of 5mC. Taken together, DNMT1 alone is insufficient to maintain DNA methylation but requires the action of DNMT3A/3B that act as a “dimmer switches”.
2016-06-03 | GSE70722 | GEO
Project description:DNA methylation is the net result of deposition by DNA methyltransferases (DNMT1, 3A and 3B) and removal by the Ten-Eleven Translocation 1-3 (TET1-3) family of proteins and/or passive loss by replication. The relative contribution of the individual enzymes and pathways is only partially understood. Here we comprehensively analyzed and mathematically simulated the dynamics of DNA de-methylation during the reprogramming of the hypermethylated serum-cultured mouse embryonic stem cells (ESCs) to the hypomethylated 2i-cultured ground state of mESC. We show that DNA demethylation readily occurs in TET[1-/-, 2-/-] ESCs with similar kinetics as their WT littermates. Vitamin C activation of TET causes accelerated and more profound DNA demethylation without markedly affecting reprogramming kinetics. We developed a mathematical model that highly accurately predicts the global level of 5methyl- and 5hydroxymethylcytosine during the transition. Modeling and experimental validation show that the concentration of DNMT3A and DNMT3B determines the steady state level of global DNA methylation and absence of DNMT3A/B even in continued presence of DNMT1 results in gradual loss of 5mC. Taken together, DNMT1 alone is insufficient to maintain DNA methylation but requires the action of DNMT3A/3B that act as a “dimmer switches”.
2016-06-03 | GSE70720 | GEO
Project description:Mammalian DNA methylation patterns are established by two de novo DNA methyltransferases DNMT3A and DNMT3B, which exhibit both redundant and distinctive methylation activities. However, the related molecular basis remains undetermined. Through comprehensive structural, enzymology and cellular characterizations of DNMT3A and DNMT3B, here we uncovered distinct and interrelated modes-of-action underlying their CpG site and flanking sequence interaction. Strikingly, K777 of DNMT3B makes direct contacts with the DNA base at the +1 flank position of the cytosine methylation site, which contrasts with its counterpart in DNMT3A that forms base-specific contacts with the CpG site. Consequently, there is a divergent substrate and flanking sequence preference between DNMT3A and DNMT3B in vitro and in cells, thus providing an explanation for site-specific epigenomic alterations seen in ICF syndrome patients with DNMT3B mutations. Together, this study reveals crucial, yet complicated interplays of DNMT3s, DNA sequences and resultant methylation.
2020-06-18 | GSE145899 | GEO