Project description:Multiple epigenetic pathways underlie the temporal order of DNA replication (replication timing) in the context of development and disease. DNA methylation by DNA methyltransferases (DNMTs) and downstream chromatin reorganization and transcriptional changes are thought to impact DNA replication, yet this remains to be comprehensively tested. Using cell biological and genome-wide approaches to measure replication timing, we identified a number of genomic regions undergoing subtle but reproducible replication timing changes in various DNMT-mutant mouse ES cell lines that include a line with a drug-inducible DNMT3a2 expression system. Replication timing within pericentromeric heterochromatin (PH) correlates with redistribution of H3K27me3 induced upon DNA hypomethylation: later replicating PH coincides with H3K27me3 enriched regions. In contrast, this relationship with H3K27me3 was not evident at chromosomal arm regions that undergo either early-to-late (EtoL) or late-to-early (LtoE) replication timing switching upon loss of DNMTs. Interestingly, transcriptional up- and down-regulation frequently coincide with earlier and later shifts in replication timing of chromosomal arm regions, respectively. Our study revealed previously unrecognized complex and diverse roles of DNMTs in shaping the mammalian DNA replication landscape. We investigated the effect of Dnmt3a2 expression in the transcription profile of Dnmt3a and 3b double knockout (DKO) ES cells.
Project description:Multiple epigenetic pathways underlie the temporal order of DNA replication (replication timing) in the context of development and disease. DNA methylation by DNA methyltransferases (DNMTs) and downstream chromatin reorganization and transcriptional changes are thought to impact DNA replication, yet this remains to be comprehensively tested. Using cell biological and genome-wide approaches to measure replication timing, we identified a number of genomic regions undergoing subtle but reproducible replication timing changes in various DNMT-mutant mouse ES cell lines that include a line with a drug-inducible DNMT3a2 expression system. Replication timing within pericentromeric heterochromatin (PH) correlates with redistribution of H3K27me3 induced upon DNA hypomethylation: later replicating PH coincides with H3K27me3 enriched regions. In contrast, this relationship with H3K27me3 was not evident at chromosomal arm regions that undergo either early-to-late (EtoL) or late-to-early (LtoE) replication timing switching upon loss of DNMTs. Interestingly, transcriptional up- and down-regulation frequently coincide with earlier and later shifts in replication timing of chromosomal arm regions, respectively. Our study revealed previously unrecognized complex and diverse roles of DNMTs in shaping the mammalian DNA replication landscape.
Project description:This SuperSeries is composed of the following subset Series: GSE13075: SIRT1 and H1AcK26 promoter-association in mouse ES cells changes upon oxidative stress GSE13120: Age-related gene expression changes in mouse neocortex Refer to individual Series