GSE107690 G-quadruplex structures moulds the DNA methylome

Contributors : Jochen Spiegel ; Avazeh Ghanbarian ; Giovanni Marsico ; Dario Beraldi ; Robert H änsel-Hertsch ; Shiqing Mao ; David Tannahill ; Shankar BalasubramanianSeries Type : Genome binding/occupancy profiling by high throughput sequencingOrganism : Homo sapiensControl of DNA methylation level is critical for gene regulation, and the factors that govern hypomethylation at CpG islands (CGIs) are still being uncovered. Here, we provide evidence that G-quadruplex (G4) DNA secondary structures are genomic features that influence methylation at CGIs. We show that the presence of G4 structure is tightly associated with CGI hypomethylation. Surprisingly, we find that these G4 sites are enriched for DNA methyltransferase 1 (DNMT1) occupancy, which is consistent with our biophysical observations that DNMT1 exhibits higher binding affinity for G4s as compared to duplex, hemi-methylated or single-stranded DNA. The biochemical assays also show that the G4 structure itself, rather than sequence, inhibits DNMT1 enzymatic activity. Based on these data, we propose that G4 formation sequesters DNMT1 thereby protecting certain CGIs from methylation and inhibiting local methylation.

Source: GEO: Gene Expression Omnibus - July 16, 2018 Category: Genetics & Stem Cells Tags: Genome binding/occupancy profiling by high throughput sequencing Homo sapiens Source Type: research