Topoisomerase II regulates the maintenance of DNA methylation [Cell Biology]

December 1st, 2014 by Lu, L.-Y., Kuang, H., Korakavi, G., Yu, X.

The maintenance of DNA methylation in nascent DNA is a critical event for numerous biological processes. Following DNA replication, DNMT1 is the key enzyme that strictly copies the methylation pattern from the parental strand to the nascent DNA. However, the mechanism underlying this highly specific event is not thoroughly understood. In this study, we have identified topoisomerase II (TopoIIα) as a novel regulator of the maintenance DNA methylation. UHRF1, a protein important for global DNA methylation, interacts with TopoIIα and regulates its localization to hemi-methylated DNA. TopoIIα decatenates the hemi-methylated DNA following replication, which might facilitate the methylation of the nascent strand by DNMT1. Inhibiting this activity impairs DNA methylation at multiple genomic loci. Taken together, we have uncovered a novel mechanism during the maintenance of DNA methylation.