DNA methylation of yound male wild type and dSpin1 knockout mice
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ABSTRACT: In the male mouse germline, PIWI-interacting RNAs (piRNAs), bound by the PIWI protein MIWI2 (PIWIL4), guide the DNA methylation of young active transposable elements (TEs) through SPOCD1.
Project description:In the male mouse germline, PIWI-interacting RNAs (piRNAs), bound by the PIWI protein MIWI2 (PIWIL4), guide the DNA methylation of young active transposable elements (TEs) through SPOCD1. We identified loss-of-function variants in human SPOCD1 that cause male infertility and defective TE silencing. One SPOCD1 pathogenic allele encodes a truncated protein that lacks the conserved carboxy-terminus. We demonstrated that this deleted region interacts with C19ORF84. In mouse foetal germ cells, the nuclear protein C19ORF84 is required for the association of SPOCD1 with DNMT3L, an essential component of the de novo methylation machinery. In summary, we identified a conserved role for SPOCD1 in safeguarding the continuity of the human germline and discovered C19ORF84, an uncharacterised protein essential for 15 orchestrating piRNA-directed DNA methylation.
Project description:In mammals, the acquisition of the germline from the soma provides the germline with an essential challenge, the necessity to erase and reset genomic methylation. In the male germline RNA-directed DNA methylation silences young active transposable elements (TEs). The PIWI protein MIWI2 (PIWIL4) and its associated PIWI-interacting RNAs (piRNAs) are proposed to tether MIWI2 to nascent TE transcripts and instruct DNA methylation. The mechanism by which MIWI2 directs de novo TE methylation is poorly understood but central to the immortality of the germline. Here, we define the interactome of MIWI2 in foetal gonocytes that are undergoing de novo genome methylation and identify a novel MIWI2-associated factor, SPOCD1, that is essential for young TE methylation and silencing. The loss of Spocd1 in mice results in male specific infertility and does not impact on piRNA biogenesis nor localization of MIWI2 to the nucleus. SPOCD1 is a nuclear protein and its expression is restricted to the period of de novo genome methylation. We found SPOCD1 co-purified in vivo with DNMT3L and DNMT3A, components of the de novo methylation machinery as well as constituents of the NURD and BAF chromatin remodelling complexes. We propose a model whereby tethering of MIWI2 to a nascent TE transcript recruits repressive chromatin remodelling activities and the de novo methylation apparatus through its association with SPOCD1. In summary, we have identified a novel and essential executor of mammalian piRNA-directed DNA methylation.
Project description:The PIWI protein MIWI2 and its associated PIWI-interacting RNAs (piRNAs) instruct DNA methylation of young active transposable elements (TEs) in the male germline. Here we show that MIWI2 associates with TEX15 in foetal gonocytes. TEX15 is predominantly a nuclear protein that is not required for piRNA biogenesis but is essential for piRNA-directed TE de novo methylation and silencing. In summary, TEX15 is an essential executor of mammalian piRNA-directed DNA methylation.
Project description:In this study, we validated 992 previously identified differentially methylated regions (DMRs) in colorectal precancerous lesions compared to adjacent normal mucosa in a new series of 59 prospectively collected lesions and matched normal tissue using targeted bisulfite sequencing. Strong differences in methylation level were observed across the full set of validated DMRs. Based on the mean methylation levels of a panel of 30 selected DMRs tumors could be accurately classified. We thus provide a large list of validated DNA markers to be exploited in the development of noninvasive, colorectal tumor screening assays.
Project description:Epigenetic drugs actively altering the epigenome of tumours have been developed for use in anti-cancer therapies. However, these drugs could potentially also affect the DNA methylome of spermatozoa that seems to be essential for male fertility. Here, we analysed possible direct and transgenerational effects of the epigenetic drug decitabine on the DNA methylome of spermatozoa. Our analysis revealed the absence of gross differences between the spermatozoal methylome of decitabine treated and untreated animals as well as between their F3 generations. Interestingly, the methylomes of spermatozoa from the selected mice of the F3-generations were also highly similar to the analysed parental samples. We studied genome-wide DNA methylation changes in decitabine treated mice and their F3-generation. For this, we treated male C57BL/6 mice (seven weeks old) for seven weeks (intraperitoneal, three times per week) with the DNMT inhibitor decitabine (5-aza-2'-deoxycytidine, 0.1 µg/g, n = 17) or with vehicle (7.5 % dimethyl sulfoxide in phosphate buffered saline, n = 16). The dose of decitabine per treatment was chosen according to the clinical application regimens in humans and refer to previous mice studies using this drug (Kelly et al, 2003; Oakes et al, 2007). For the investigation of transgenerational effects, 10 treated and untreated male mice were mated with four untreated female C57BL/6 mice each. The offspring was considered as F1-generation. The F2- and F3-generations were obtained by an identical mating scheme. Thus, only the P-generation males were treated with decitabine or control vehicle, the F1-, F2- and F3-generations were not subjected to any treatment. During this study, all mice were housed at 24 °C on a 12-h light, 12-h dark cycle and provided with food and tap-water ad libitum.
Project description:The de novo DNA methyltransferases Dnmt3a and Dnmt3b are of crucial importance in hematopoietic stem cells, and Dnmt3b has recently been shown to play a role in genic methylation. Forced Dnmt3b expression induced widespread DNA hypermethylation in myc-bcl2 induced leukemias, especially at promoters and gene bodies of stem cell-related genes. MLL-AF9 induced leukemogenesis showed much less pronounced DNA hypermethylation upon Dnmt3b expression. Nonetheless, leukemogenesis was delayed in both models with a shared core set of DNA hypermethylated regions and suppression of stem cell-related genes. Our findings indicate a critical role for Dnmt3b-mediated DNA methylation in leukemia development and maintenance of LSC function. To investigate how Dnmt3b-mediated DNA methylation affects leukemogenesis, we analyzed leukemia development under conditions of high and physiological methylation levels in a tetracycline-inducible knockin mouse model. High expression of Dnmt3b slowed leukemia development in serial transplantations and impaired leukemia stem cell (LSC) function.
Project description:DNA methylation is an important epigenetic regulator of gene expression. Recent studies have revealed widespread associations between genetic variation and methylation levels. However, the mechanistic links between genetic variation and methylation remain unclear. To begin addressing this gap, we collected methylation data at ~300,000 loci in lymphoblastoid cell lines (LCLs) from 64 HapMap Yoruba individuals, and genome-wide bisulfite sequence data in ten of these individuals. We identified (at an FDR of 10%) 13,915 *cis* methylation QTLs (meQTLs), i.e., CpG sites in which changes in DNA methylation are associated with genetic variation at proximal loci. We found that meQTLs are frequently associated with changes in methylation at multiple CpGs across regions of up to 3 kb. Interestingly, meQTLs are also frequently associated with variation in other properties of gene regulation, including histone modifications, DNase I accessibility, chromatin accessibility, and expression levels of nearby genes. These observations suggest that genetic variants may lead to coordinated molecular changes in all of these regulatory phenotypes. One plausible driver of coordinated changes in different regulatory mechanisms is variation in transcription factor (TF) binding. Indeed, we found that SNPs that change predicted TF binding affinities are significantly enriched for associations with DNA methylation at nearby CpGs. Whole genomic DNA from 10 Yoruba HapMap individuals and spiked in unmethylated lambda phage DNA was bisuflite converted using the Invitrogen MethylCode Bisulfite Conversion Kit and sequenced using a Illumina HiSeq 2000
Project description:The reprogramming of parental methylomes is essential for embryonic development. In mammals, paternal 5-methylcytosines (5mCs) have been proposed to be actively converted to oxidized bases. These paternal oxidized bases and maternal 5mCs are believed to be passively diluted by cell divisions. By generating single-base resolution, allele-specific DNA methylomes from mouse gametes, early embryos, and primordial germ cell (PGC), as well as single-base-resolution maps of oxidized cytosine bases for early embryos, we report the existence of 5hmC and 5fC in both maternal and paternal genomes and find that 5mC or its oxidized derivatives, at the majority of demethylated CpGs, are converted to unmodified cytosines independent of passive dilution from gametes to four-cell embryos. Therefore, we conclude that paternal methylome and at least a significant proportion of maternal methylome go through active demethylation during embryonic development. Additionally, all the known imprinting control regions (ICRs) were classified into germ-line or somatic ICRs. The cross of two mouse strains was performed using DBA/2J as the paternal strain and C57BL/6J as the maternal strain. The hybrid embryos were collected at 2-cell, 4-cell, ICM, E6.5, E7.5 stages. Female and male E13.5 PGC samples (B6; 129S4-Pou5f1tm2Jae/J) were collected from timed mating of C57BL/6J female mice. MethylC-Seq: oocytes (C57BL/6J), sperm (DBA/2J), 2-cell embryos, 4-cell embryos, ICM, E6.5 embryos, E7.5 embryos, E13.5 female PGCs and E13.5 male PGCs. TAB-Seq: 2-cell embryos. fCAB-Seq: 2-cell embryos. RNA-Seq: oocytes (C57BL/6J).
Project description:RRBS was used to analyse global imprinting gene methylation pattern of offspring from the in vitro derived spermatids like cells and normal control Global imprinting gene methylation pattern comparision of two offspring (one male and one female) from the in vitro derived spermatids like cells and two normal control mice (one male and one female)
Project description:Genome-wide erasure of DNA methylation takes place in primordial germ cells (PGCs) and early embryos but the signalling mechanisms that induce reprogramming are unknown. Here we show that inhibition of Erk1/2 and Gsk3bM-BM- signalling in mouse embryonic stem cells (ESCs) by small molecule inhibitors (PD0325901 and CHIR99021, hereafter called 2i)M-BM- induces genome-wide demethylation on a scale similar to that in PGCs and early embryos, with only major satellites, intracisternal A particles (IAPs) and imprinted genes relatively resistant to erasure. Demethylation involves oxidation of 5-methylcytosine (5mC) in part by Tet1 together with repression of theM-BM- de novoM-BM- methyltransferases (Dnmt3a, Dnmt3b) and their regulator Dnmt3L and we identify aM-BM- cis-acting regulatory region inM-BM- Dnmt3bM-BM- that is highly responsive to signalling. Notably, this epigenetic and transcriptional ground state of pluripotency resembles closely that of inner cell mass (ICM) cells of the blastocyst. These insights provide a novel framework for understanding how signalling pathways regulate epigenetic reprogramming. mRNA and methylation profiles of ES cells passaged with or without 2i inhibitors were generated by deep sequencing, using Illumina GAIIx and HiSeq.