The centromeric nucleosome

摘要

Centromeres are marked epigenetically by the assembly of nucleosomes containing CENP-A, a centromere-specific histone H3 variant. Tachiwana et al. report the crystal structure of the human centromeric nucleosome bound to DNA. They find a canonical arrangement of an octamer of histone proteins, with DNA wrapped in a left-handed superhelix. There is flexibility in the DNA regions at the entrance and exit of the nucleosome, and a loop in CENP-A may help to stabilize the nucleosomes incorporation into centromeric chromatin. The structure - the first view of the CENP-A-containing nucleosome - helps to clarify various models that have been debated in the literature. Crystal structure of the human centromeric nucleosome containing CENP-A H Tachiwana etal.