DNA G-quadruplex structures mould the DNA methylome
Nature Structural and Molecular Biology
MetadataShow full item record
Balasubramanian, S., Mao, S., Ghanbarian, A., Spiegel, J., Martinez Cuesta, S., Beraldi, D., Di Antonio, M., et al. (2018). DNA G-quadruplex structures mould the DNA methylome. Nature Structural and Molecular Biology https://doi.org/10.1038/s41594-018-0131-8
Control 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 in the human genome. 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.
This work is supported by a core CRUK award (C14303/A17197). S.B. is a Senior Investigator of the Wellcome Trust (grant no. 099232/z/12/z). JS is a Marie Curie Fellow of the European Union (747297-QAPs-H2020-MSCA-IF-2016).
Wellcome Trust (099232/Z/12/Z)
Cancer Research UK (CB4330)
European Commission Horizon 2020 (H2020) Marie Sk?odowska-Curie actions (747297)
External DOI: https://doi.org/10.1038/s41594-018-0131-8
This record's URL: https://www.repository.cam.ac.uk/handle/1810/280632