Synonyms:
Antigen p25; HP1-α; CBX5; CBX5_HUMAN; Chromobox homolog 5 (HP1 alpha homolog, Drosophila); Chromobox homolog 5; Chromobox protein homolog 5; Heterochromatin protein 1 alpha; Heterochromatin protein 1; Heterochromatin protein 1 homolog alpha; HP1 alpha; HP1 alpha homolog; HP1; HP1A; HP1Hs alpha.
Introduction:
Heterochromatin protein-1 (HP1) is a methyl-lysine binding protein localized at heterochromatin sites, where it mediates gene silencing. It has been shown that mammalian methyltransferases that selectively methylate histone H3 on lysine-9 generate a binding site for HP1 proteins, a family of heterochromatic adaptor molecules implicated in both gene silencing and supranucleosomal chromatin structure. High-affinity in vitro recognition of a methylated histone H3 peptide by HP1 requires a functional chromodomain. Thus, the HP1 chromodomain is a specific interaction motif for the methyl epitope on lysine-9 of histone H3. In vivo, heterochromatin association of HP1 proteins is lost in Suv39h double-null primary mouse fibroblasts but is restored after reintroduction of a catalytically active SUV39H1 HMTase.