Coordinated methyl and RNA binding is required for heterochromatin localization of mammalian HP1 α

Christian Muchardt (1) , Marie Guillemé (1) , Jacob-Sebastian Seeler (2) , Didier Trouche (3) , Anne Dejean (2) , Moshe Yaniv (1)

1 Expression Génétique et Maladies
2 Recombinaison et Expression Génétique
3 LBME - Laboratoire de biologie moléculaire eucaryote

In mammalian cells, as in Schizosaccharomyces pombe and Drosophila, HP1 proteins bind histone H3 tails methylated on lysine 9 (K9). However, whereas K9-methylated H3 histones are distributed throughout the nucleus, HP1 proteins are enriched in pericentromeric heterochromatin. This observation suggests that the methyl-binding property of HP1 may not be sufficient for its heterochromatin targeting. We show that the association of HP1alpha with pericentromeric heterochromatin depends not only on its methyl-binding chromo domain but also on an RNA-binding activity present in the hinge region of the protein that connects the conserved chromo and chromoshadow domains. Our data suggest the existence of complex heterochromatin binding sites composed of methylated histone H3 tails and RNA, with each being recognized by a separate domain of HP1alpha.

Domains: Life Sciences [q-bio]

Christian Muchardt, Marie Guillemé, Jacob-Sebastian Seeler, Didier Trouche, Anne Dejean, et al.. Coordinated methyl and RNA binding is required for heterochromatin localization of mammalian HP1 α. EMBO Reports, 2002, 3 (10), pp.975-981. ⟨10.1093/embo-reports/kvf194⟩. ⟨pasteur-03237075⟩