Hide A. Konishi

eLife Assessment This study provides valuable mechanistic insight into the mutually exclusive distributions of the histone variant H2A.Z and DNA methylation by testing two hypotheses: (i) that DNA methylation suppresses H2A.Z deposition by ATP-dependent chromatin remodelling complexes, and (ii) that DNA methylation destabilizes H2A.Z nucleosomes, thereby preventing H2A.Z retention.

Abstract The histone variant H2A.Z and DNA methylation are enriched at mutually exclusive genomic segments, though its mechanistic bases remain unclear. Here, we examine impacts of DNA methylation on the intrinsic stability of the H2A.Z nucleosome and chaperone-mediated H2A.Z deposition. Cryo-EM and endonuclease analyses suggest that DNA methylation subtly increases the openness and accessibility of the H2A.Z nucleosome on satellite II-derived DNA sequences.

eLife Assessment This study follows up on Arimura et al's powerful new method MagIC-Cryo-EM for imaging native complexes at high resolution. Using a clever design embedding protein spacers between the antibody and the nucleosomes purified, thereby minimizing interference from the beads, the authors concentrate linker histone variant H1.8 containing nucleosomes.