Chromatin dynamics and genome-wide profiling of repetitive elements during early mammalian embryogenesis.
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE39849 | GEO | 2013/01/27
SECONDARY ACCESSION(S): PRJNA171857
REPOSITORIES: GEO
Similar Datasets
Project description:We have used repetitive elements, including retrotransposons, as model loci to address how and when heterochromatin forms during development. High throughput RNA-sequencing using a Nano-CAGE protocol throughout early embryogenesis revealed that the expression of repetitive elements is abundant in embryonic cells, highly dynamic and stage-specific, with most repetitive elements becoming repressed before implantation. Furthermore, we show that Line L1 elements and IAP retrotransposons become reactivated from both parental genomes in mouse embryos after fertilisation, indicating an open chromatin configuration at the beginning of development. Our data show that the reprogramming process that follows fertilisation is accompanied by a robust transcriptional activation of retrotransposons and suggests that expression of repetitive elements is initially regulated through an RNA-dependent mechanism in mammals. Genome Wide profiling of CAGE transcripts using Nano-CAGE and RNAseq in oocytes and 3 different stages of mouse pre-implantation development
2013-01-27 | E-GEOD-39849 | biostudies-arrayexpress
Project description:In mammals, DNA methylation is essential for protecting repetitive sequences from aberrant transcription, translocation, and homologous recombination. However, DNA hypomethylation occurs during specific developmental stages (e.g. preimplantation embryos) and in certain cell types (e.g., primordial germ cells). The absence of dysregulated repetitive elements in these cells suggests the existence of alternative mechanisms that prevent genome instability triggered by DNA hypomethylation. In this report, we seek to elucidate the factors that play a critical role in ensuring genome stability by focusing on DAXX and ATRX, two proteins that have been linked to transcriptional control and epigenetic regulation. We carried out ChIP-seq and RNA-seq analyses to compare the genome-wide binding and transcriptome profiles of DAXX and ATRX in mouse ES (mES) cells triple knocked out for the three mammalian DNA methyltransferases (DNMTs) (TKO cells) to those in wildtype mES cells. Our data indicate that DAXX and ATRX are distinct in their chromatin-binding profiles and highly co-enriched at tandem repetitive elements. Global DNA hypomethylation, as was the case in TKO cells, further promoted the recruitment of the DAXX/ATRX complex to tandem repeat sequences including IAP (intracisternal A‐particle) retrotransposons and telomeres. Inhibition of DAXX or ATRX in cells with hypomethylated genomes (e.g., TKO cells, mES cells cultured in ground-state conditions, and preimplantation embryos) increased aberrant transcriptional de-repression of repeat elements and dysfunction at telomeres. Furthermore, we provide evidence that DAXX/ATRX-dependent silencing may occur through DAXX’s interaction with SUV39H1 and increased H3K9me3 on repetitive sequences. Our study suggests that DAXX and ATRX are important for safeguarding the genome, particularly in silencing repetitive elements in the absence of DNA methylation. We tested the hypothesis that the DAXX/ATRX complex participates in protecting repetitive elements in the absence of DNA methylation. To this end, we investigated genome-wide chromatin targeting of DAXX and ATRX in wildtype mES cells, and in mES cells that exhibit extensive loss of DNA methylation due to homozygous knockout of all three DNA.
2015-07-15 | E-GEOD-70811 | biostudies-arrayexpress
Project description:DNA methylation is an essential epigenetic modification, present in both unique DNA sequences and repetitive elements, but its exact function in repetitive elements remains obscure. Here, we describe the genome-wide comparative analysis of the 5mC, 5hmC, 5fC and 5caC profiles of repetitive elements in mouse embryonic fibroblasts and mouse embryonic stem cells. We provide evidence for distinct and highly specific DNA methylation/oxidation patterns of the repetitive elements in both cell types, which mainly affect CA repeats and evolutionary conserved mouse-specific transposable elements including IAP-LTRs, SINEs B1m/B2m and L1Md-LINEs. DNA methylation controls the expression of these retro-elements, which are clustered at specific locations in the mouse genome. We show that TDG is implicated in the regulation of their unique DNA methylation/oxidation signatures and their dynamics. Our data suggest the existence of novel epigenetic code for the most recently acquired evolutionary conserved repeats that could play a major role in cell differentiation. This SuperSeries is composed of the SubSeries listed below.
2017-02-22 | GSE66438 | GEO
Project description:DNA methylation is an essential epigenetic modification, present in both unique DNA sequences and repetitive elements, but its exact function in repetitive elements remains obscure. Here, we describe the genome-wide comparative analysis of the 5mC, 5hmC, 5fC and 5caC profiles of repetitive elements in mouse embryonic fibroblasts and mouse embryonic stem cells. We provide evidence for distinct and highly specific DNA methylation/oxidation patterns of the repetitive elements in both cell types, which mainly affect CA repeats and evolutionary conserved mouse-specific transposable elements including IAP-LTRs, SINEs B1m/B2m and L1Md-LINEs. DNA methylation controls the expression of these retro-elements, which are clustered at specific locations in the mouse genome. We show that TDG is implicated in the regulation of their unique DNA methylation/oxidation signatures and their dynamics. Our data suggest the existence of novel epigenetic code for the most recently acquired evolutionary conserved repeats that could play a major role in cell differentiation.
2017-02-22 | GSE77769 | GEO
Project description:DNA methylation is an essential epigenetic modification, present in both unique DNA sequences and repetitive elements, but its exact function in repetitive elements remains obscure. Here, we describe the genome-wide comparative analysis of the 5mC, 5hmC, 5fC and 5caC profiles of repetitive elements in mouse embryonic fibroblasts and mouse embryonic stem cells. We provide evidence for distinct and highly specific DNA methylation/oxidation patterns of the repetitive elements in both cell types, which mainly affect CA repeats and evolutionary conserved mouse-specific transposable elements including IAP-LTRs, SINEs B1m/B2m and L1Md-LINEs. DNA methylation controls the expression of these retro-elements, which are clustered at specific locations in the mouse genome. We show that TDG is implicated in the regulation of their unique DNA methylation/oxidation signatures and their dynamics. Our data suggest the existence of novel epigenetic code for the most recently acquired evolutionary conserved repeats that could play a major role in cell differentiation.
2017-02-22 | GSE77768 | GEO
Project description:DNA methylation is an essential epigenetic modification, present in both unique DNA sequences and repetitive elements, but its exact function in repetitive elements remains obscure. Here, we describe the genome-wide comparative analysis of the 5mC, 5hmC, 5fC and 5caC profiles of repetitive elements in mouse embryonic fibroblasts and mouse embryonic stem cells. We provide evidence for distinct and highly specific DNA methylation/oxidation patterns of the repetitive elements in both cell types, which mainly affect CA repeats and evolutionary conserved mouse-specific transposable elements including IAP-LTRs, SINEs B1m/B2m and L1Md-LINEs. DNA methylation controls the expression of these retro-elements, which are clustered at specific locations in the mouse genome. We show that TDG is implicated in the regulation of their unique DNA methylation/oxidation signatures and their dynamics. Our data suggest the existence of novel epigenetic code for the most recently acquired evolutionary conserved repeats that could play a major role in cell differentiation.
2017-02-22 | GSE77767 | GEO
Project description:Upon fertilisation, the highly differentiated gametes reprogram to a totipotent state to initiate a new developmental programme. Approximately half of the mammalian genome is composed of repetitive elements, including retrotransposons, some of which are transcriptionally activated after fertilisation. It is generally assumed that retrotransposons become activated as a side-effect of the large chromatin remodelling underlying the epigenetic reprogramming of the gametes. Here, we have used a targeted epigenomic approach to address whether specific families of retrotransposons play a direct role in chromatin organisation and developmental progression after fertilisation. Using this approach, we demonstrate that precocious silencing of LINE-1 reduces chromatin accessibility, while their prolonged activation prevents gradual chromatin compaction, natural to developmental progression. Preventing LINE-1 activation and interfering with their silencing results in a reduced developmental rate independently of the coding nature of the LINE-1 transcript, suggesting that LINE-1 functions primarily at the chromatin level. Our data suggest that activation of LINE-1 regulates global chromatin accessibility at the beginning of development and indicate that activation of retrotransposons is an integral part of the developmental programme.
2017-07-07 | GSE98436 | GEO
Project description:In mammals, DNA methylation is essential for protecting repetitive sequences from aberrant transcription, translocation, and homologous recombination. However, DNA hypomethylation occurs during specific developmental stages (e.g. preimplantation embryos) and in certain cell types (e.g., primordial germ cells). The absence of dysregulated repetitive elements in these cells suggests the existence of alternative mechanisms that prevent genome instability triggered by DNA hypomethylation. In this report, we seek to elucidate the factors that play a critical role in ensuring genome stability by focusing on DAXX and ATRX, two proteins that have been linked to transcriptional control and epigenetic regulation. We carried out ChIP-seq and RNA-seq analyses to compare the genome-wide binding and transcriptome profiles of DAXX and ATRX in mouse ES (mES) cells triple knocked out for the three mammalian DNA methyltransferases (DNMTs) (TKO cells) to those in wildtype mES cells. Our data indicate that DAXX and ATRX are distinct in their chromatin-binding profiles and highly co-enriched at tandem repetitive elements. Global DNA hypomethylation, as was the case in TKO cells, further promoted the recruitment of the DAXX/ATRX complex to tandem repeat sequences including IAP (intracisternal A‐particle) retrotransposons and telomeres. Inhibition of DAXX or ATRX in cells with hypomethylated genomes (e.g., TKO cells, mES cells cultured in ground-state conditions, and preimplantation embryos) increased aberrant transcriptional de-repression of repeat elements and dysfunction at telomeres. Furthermore, we provide evidence that DAXX/ATRX-dependent silencing may occur through DAXX’s interaction with SUV39H1 and increased H3K9me3 on repetitive sequences. Our study suggests that DAXX and ATRX are important for safeguarding the genome, particularly in silencing repetitive elements in the absence of DNA methylation.
2015-07-15 | GSE70811 | GEO
Project description:In mammals, DNA methylation is essential for protecting repetitive sequences from aberrant transcription, translocation, and homologous recombination. However, DNA hypomethylation occurs during specific developmental stages (e.g. preimplantation embryos) and in certain cell types (e.g., primordial germ cells). The absence of dysregulated repetitive elements in these cells suggests the existence of alternative mechanisms that prevent genome instability triggered by DNA hypomethylation. In this report, we seek to elucidate the factors that play a critical role in ensuring genome stability by focusing on DAXX and ATRX, two proteins that have been linked to transcriptional control and epigenetic regulation. We carried out ChIP-seq and RNA-seq analyses to compare the genome-wide binding and transcriptome profiles of DAXX and ATRX in mouse ES (mES) cells triple knocked out for the three mammalian DNA methyltransferases (DNMTs) (TKO cells) to those in wildtype mES cells. Our data indicate that DAXX and ATRX are distinct in their chromatin-binding profiles and highly co-enriched at tandem repetitive elements. Global DNA hypomethylation, as was the case in TKO cells, further promoted the recruitment of the DAXX/ATRX complex to tandem repeat sequences including IAP (intracisternal A‐particle) retrotransposons and telomeres. Inhibition of DAXX or ATRX in cells with hypomethylated genomes (e.g., TKO cells, mES cells cultured in ground-state conditions, and preimplantation embryos) increased aberrant transcriptional de-repression of repeat elements and dysfunction at telomeres. Furthermore, we provide evidence that DAXX/ATRX-dependent silencing may occur through DAXX’s interaction with SUV39H1 and increased H3K9me3 on repetitive sequences. Our study suggests that DAXX and ATRX are important for safeguarding the genome, particularly in silencing repetitive elements in the absence of DNA methylation.
2015-07-15 | GSE70849 | GEO
Project description:Background: Global DNA methylation contributes to genomic integrity by supressing repeat associated transposition events. Several chromatin factors are required in addition to DNA methyltransferases to maintain DNA methylation at intergenic and satellite repeats. Embryos lacking Lsh, a member of the SNF2 superfamily of chromatin helicases, are hypomethylated. The interaction of Lsh with the de novo methyltransferase, Dnmt3b, facilitates the deposition of DNA methylation at stem cell genes. We wished to determine if a similar targeting mechanism operates to maintain DNA methylation at repetitive sequences. Results: We used HELP-seq to map genome wide DNA methylation patterns in Lsh-/- and Dnmt3b-/- somatic cells. DNA methylation is predominantly lost from specific genomic repeats in Lsh-/- cells: LTR-retrotransposons, LINE-1 repeats and mouse satellites. RNA-seq experiments demonstrate that specific IAP (Intracisternal A-type particle) LTRs and satellites, but not LINE-1 elements, are aberrantly transcribed inLsh-/- cells. LTR hypomethylation in Dnmt3b-/- cells is moderate and hypomethylated repetitive elements (IAP, LINE-1 and satellite) are silent. Chromatin immunoprecipitation (ChIP) indicates that repressed LINE-1 elements gain H3K4me3, but H3K9me3 levels are unaltered in Lsh-/- cells, indicating that DNA hypomethylation alone is not permissive for their transcriptional activation. Mis-expressed IAPs and satellites lose H3K9me3 and gain H3K4me3 in Lsh-/- cells. Conclusions: Our study emphasizes that regulation of repetitive elements by DNA methylation is selective and context dependent. We propose a model where Lsh is specifically required at a precise developmental window to target de novo methylation to repeat sequences, which is subsequently maintained by Dnmt1 in somatic cells to enforce repeat silencing thus contributing to genomic integrity. Two pairs of RNA samples compared: WT and Lsh-/- RNA isolations from tail-tip fibroblasts; WT and Lsh-/- RNA isolations from E13.5 mouse embryos.
2013-12-09 | E-GEOD-52477 | biostudies-arrayexpress