MBD4 loss results in global reactivation of promoters and retroelements with low methylated CpG density.
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PROVIDER: PRJNA276709 | ENA |
REPOSITORIES: ENA
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Project description:Inherited defects in the base-excision repair gene MBD4 predispose individuals to adenomatous polyposis and colorectal cancer, which is characterized by an accumulation of C>T transitions resulting from spontaneous deamination of 5’-methylcytosine. Despite its significance, this DNA repair pathway is still poorly understood. Here we show that the protein MBD4 is required for DNA methylation maintenance and G/T mismatch repair. Transcriptome and methylome analyses reveal a genome-wide hypomethylation of promoters, gene bodies and repetitive elements in the absence of MBD4 in vivo. Methylation mark loss is accompanied by a broad transcriptional derepression phenotype affecting promoters and retroelements with low methylated CpG density. MBD4 in vivo forms a complex with the mismatch repair proteins (MMR), which exhibits high bi-functional glycosylase/AP-lyase endonuclease specific activity towards methylated DNA substrates containing a G/T mismatch. Experiments using recombinant proteins reveal that the association of MBD4 with the MMR protein MLH1 is required for this activity. The described data identify MBD4 as an enzyme specifically designed to repair deaminated 5-methylcytosines and illustrates how MBD4 functions in normal and pathological conditions.
2022-01-10 | GSE84318 | GEO
Project description:Inherited defects in the base-excision repair gene MBD4 predispose individuals to adenomatous polyposis and colorectal cancer, which is characterized by an accumulation of C>T transitions resulting from spontaneous deamination of 5’-methylcytosine. Despite its significance, this DNA repair pathway is still poorly understood. Here we show that the protein MBD4 is required for DNA methylation maintenance and G/T mismatch repair. Transcriptome and methylome analyses reveal a genome-wide hypomethylation of promoters, gene bodies and repetitive elements in the absence of MBD4 in vivo. Methylation mark loss is accompanied by a broad transcriptional derepression phenotype affecting promoters and retroelements with low methylated CpG density. MBD4 in vivo forms a complex with the mismatch repair proteins (MMR), which exhibits high bi-functional glycosylase/AP-lyase endonuclease specific activity towards methylated DNA substrates containing a G/T mismatch. Experiments using recombinant proteins reveal that the association of MBD4 with the MMR protein MLH1 is required for this activity. The described data identify MBD4 as an enzyme specifically designed to repair deaminated 5-methylcytosines and illustrates how MBD4 functions in normal and pathological conditions.
2022-01-10 | GSE84497 | GEO
Project description:Inherited defects in the base-excision repair gene MBD4 predispose individuals to adenomatous polyposis and colorectal cancer, which is characterized by an accumulation of C>T transitions resulting from spontaneous deamination of 5’-methylcytosine. Despite its significance, this DNA repair pathway is still poorly understood. Here we show that the protein MBD4 is required for DNA methylation maintenance and G/T mismatch repair. Transcriptome and methylome analyses reveal a genome-wide hypomethylation of promoters, gene bodies and repetitive elements in the absence of MBD4 in vivo. Methylation mark loss is accompanied by a broad transcriptional derepression phenotype affecting promoters and retroelements with low methylated CpG density. MBD4 in vivo forms a complex with the mismatch repair proteins (MMR), which exhibits high bi-functional glycosylase/AP-lyase endonuclease specific activity towards methylated DNA substrates containing a G/T mismatch. Experiments using recombinant proteins reveal that the association of MBD4 with the MMR protein MLH1 is required for this activity. The described data identify MBD4 as an enzyme specifically designed to repair deaminated 5-methylcytosines and illustrates how MBD4 functions in normal and pathological conditions.
2022-01-10 | GSE84319 | GEO
Project description:BackgroundInherited defects in the base-excision repair gene MBD4 predispose individuals to adenomatous polyposis and colorectal cancer, which is characterized by an accumulation of C > T transitions resulting from spontaneous deamination of 5'-methylcytosine.MethodsHere, we have investigated the potential role of MBD4 in regulating DNA methylation levels using genome-wide transcriptome and methylome analyses. Additionally, we have elucidated its function through a series of in vitro experiments.ResultsHere we show that the protein MBD4 is required for DNA methylation maintenance and G/T mismatch repair. Transcriptome and methylome analyses reveal a genome-wide hypomethylation of promoters, gene bodies and repetitive elements in the absence of MBD4 in vivo. Methylation mark loss is accompanied by a broad transcriptional derepression phenotype affecting promoters and retroelements with low methylated CpG density. MBD4 in vivo forms a complex with the mismatch repair proteins (MMR), which exhibits high bi-functional glycosylase/AP-lyase endonuclease specific activity towards methylated DNA substrates containing a G/T mismatch. Experiments using recombinant proteins reveal that the association of MBD4 with the MMR protein MLH1 is required for this activity.ConclusionsOur data identify MBD4 as an enzyme specifically designed to repair deaminated 5-methylcytosines and underscores its critical role in safeguarding against methylation damage. Furthermore, it illustrates how MBD4 functions in normal and pathological conditions.
| S-EPMC10644448 | biostudies-literature
Project description:This SuperSeries is composed of the SubSeries listed below.
2022-01-10 | GSE66397 | GEO
Project description:MBD4 loss results in global reactivation of promoters and retroelements with low methylated CpG density.
| PRJNA328818 | ENA
Project description:MBD4 loss results in global reactivation of promoters and retroelements with low methylated CpG density.
| PRJNA328817 | ENA
Project description:MBD4 loss results in global reactivation of promoters and retroelements with low methylated CpG density.
| PRJNA329484 | ENA
Project description:Methylated mammalian promoters are transcriptionally silenced even in the presence of all the factors required for their expression. Repression requires the assembly of a methylation-dependent silencing complex that contains the TRIM28 (also known as KAP1 and TIF1β) protein. An internally controlled interaction screen identified O-linked β-N-acetylglucosamine transferase (O-GlcNAc transferase or OGT) as a protein that was complexed with TRIM28 in wild type em-bryonic stem cells but not in Dnmt1-/- cells that had severely demethylated genomes. In the ab-sence of DNA methylation, multiple proteins associated with TRIM28 failed to undergo modifica-tion by N-Acetylglucosamine (GlcNAc). Mass spectrometry identified several of these proteins as known mediators of transcriptional silencing. The most active transposon in the mouse ge-nome is the IAP LTR retrotransposon, which have been previously shown to be repressed by DNA methylation. A Bacteroides O-GlcNAc hydrolase was fused to a catalytically inactive Cas9 and targeted to methylated IAP retrotransposon promoter sequences via IAP-specific guide RNAs; fulminating reactivation of IAP transcription was induced. These data revealed that Glc-NAcylation is directly involved in the transcriptional repression of methylated promoters.
2020-05-29 | GSE93539 | GEO
Project description:Genome-wide passive DNA demethylation in cleavage-stage mouse embryos is related to the cytoplasmic localization of the maintenance methyltransferase DNMT1. However, recent studies provided evidence of the nuclear localization of DNMT1 and its contribution to the maintenance of methylation levels of imprinted regions and other genomic loci in early embryos. Using the DNA-adenine methylase identification (DamID) method, we identified Dnmt1-binding regions in 4-cell and 8-cell embryos. The unbiased distribution of Dnmt1 peaks in the genic regions (promoters and CpG islands) as well as the absence of a correlation between the Dnmt1 peaks and the expression levels of the peak-associated genes refute the active participation of Dnmt1 in the transcriptional regulation of genes in the early developmental period. Instead, Dnmt1 was found to associate with genomic retroelements in a greatly biased fashion, particularly with the long interspersed nuclear elements (LINE1) and endogenous retrovirus type-K (ERVK) sequences. Transcriptomic analysis revealed that the transcripts of the Dnmt1-enriched retroelements were overrepresented in Dnmt1 knockdown embryos. Finally, methyl-CpG-binding-domain sequencing proved that the Dnmt1-enriched retroelements, which were densely methylated in wild-type embryos, became demethylated in the Dnmt1-depleted embryos. Our results indicate that Dnmt1 is involved in the repression of retroelements through DNA methylation in early mouse development.
2020-07-19 | GSE150463 | GEO