Fiche publication
Date publication
novembre 2002
Journal
The EMBO journal
Auteurs
Membres identifiés du Cancéropôle Est :
Pr CHAMBON Pierre
,
Mr LEROUGE Thierry
Tous les auteurs :
Nielsen AL, Sanchez C, Ichinose H, Cerviño M, Lerouge T, Chambon P, Losson R
Lien Pubmed
Résumé
Mammalian heterochromatin protein 1 (HP1) alpha, HP1beta and HP1gamma are closely related non-histone chromosomal proteins that function in gene silencing, presumably by organizing higher order chromatin structures. Here, we show by co-immunoprecipitation that HP1alpha, but neither HP1beta nor HP1gamma, forms a complex with the BRG1 chromatin-remodeling factor in HeLa cells. In vitro, BRG1 interacts directly and preferentially with HP1alpha. The region conferring this preferential binding has been mapped to residues 106-180 of the HP1alpha C-terminal chromoshadow domain. Using site-directed mutagenesis, we have identified three amino acid residues I113, A114 and C133 in HP1alpha (K, P and S in HP1beta and HP1gamma) that are essential for the selective interaction of HP1alpha with BRG1. Interestingly, these residues were also shown to be critical for the silencing activity of HP1alpha. Taken together, these results demonstrate that mammalian HP1 proteins are biochemically distinct and suggest an entirely novel function for BRG1 in modulating HP1alpha-containing heterochromatic structures.
Mots clés
Amino Acid Sequence, Carrier Proteins, chemistry, Chromosomal Proteins, Non-Histone, DNA Helicases, HeLa Cells, Heterochromatin, chemistry, Humans, Molecular Sequence Data, Mutagenesis, Site-Directed, Nuclear Proteins, metabolism, Precipitin Tests, Protein Binding, Sequence Homology, Amino Acid, Transcription Factors, metabolism
Référence
EMBO J.. 2002 Nov;21(21):5797-806
