Аннотация:
HP1 is a structural component of heterochromatin.
Mammalian HP1 isoforms HP1a, HP1b, and HP1g
play different roles in genome stability, but their precise
role in heterochromatin structure is unclear.
Analysis of Hp1a
/ , Hp1b
/ , and Hp1g
/ MEFs
show that HP1 proteins have both redundant and
unique functions within pericentric heterochromatin
(PCH) and also act globally throughout the genome.
HP1a confines H4K20me3 and H3K27me3 to regions
within PCH, while its absence results in a global
hyper-compaction of chromatin associated with a
specific pattern of mitotic defects. In contrast,
HP1b is functionally associated with Suv4-20h2 and
H4K20me3, and its loss induces global chromatin
decompaction and an abnormal enrichment of
CTCF in PCH and other genomic regions. Our work
provides insight into the roles of HP1 proteins in heterochromatin
structure and genome stability.