Structural basis for activation of DNMT1

Abstract

DNMT1 is an essential enzyme that maintains genomic DNA methylation, and its function is regulated by mechanisms that are not yet fully understood. Here, we report the cryo-EM structure of nearly full-length human DNMT1 bound to its two natural activators: hemimethylated DNA and ubiquitinated histone H3. We find that a hitherto unstudied linker, between the RFTS and CXXC domains, plays a key role for activation. It contains a conserved α-helix which engages a crucial "Toggle" pocket, displacing a previously described inhibitory linker, and allowing the DNA recognition helix to spring into the active conformation. This is accompanied by large-scale reorganization of the inhibitory RFTS and CXXC domains, allowing the enzyme to gain full activity. Our results therefore provide a mechanistic basis for the activation of DNMT1, with consequences for basic research and drug design.

A review on recent advances in assays for DNMT1: a promising diagnostic biomarker for multiple human cancers

“…Nevertheless, there is no review article focusing on the detection methods of human DNA-methyltransferase 1 (DNMT1) so far. For human DNMT1 detection, conventional methodologies, including isotope labeling, [37][38][39] western blotting, [40][41][42][43][44] immunofluorescence or immunohistochemical technique, [45][46][47] and enzymelinked immunosorbent assay (ELISA), 48,49 have been frequently utilized in antibody-antigen reactions to detect the protein content or the expression status but not activity. Besides, the disadvantages of these conventional methods like hazardous radiation toxicity, tedious sample preparation and insensitivity greatly limit their wide applications.…”