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Regulation of an inducible promoter by an HP1β–HP1γ switch
Author(s) -
Mateescu Bogdan,
Bourachot Brigitte,
Rachez Christophe,
Ogryzko Vasily,
Muchardt Christian
Publication year - 2008
Publication title -
embo reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.584
H-Index - 184
eISSN - 1469-3178
pISSN - 1469-221X
DOI - 10.1038/embor.2008.1
Subject(s) - heterochromatin protein 1 , heterochromatin , promoter , transcription (linguistics) , histone , rna polymerase ii , biology , psychological repression , microbiology and biotechnology , genetics , chromatin , gene , gene expression , linguistics , philosophy
The mammalian heterochromatin protein 1 (HP1) family of proteins was recently shown to be involved in transient repression of inducible promoters. One of these promoters is the HIV1 long terminal repeat, which, during viral latency, recruits a non‐processive RNA polymerase II (RNAPII) that synthesizes a short regulatory transcript. Here, we have used this promoter to examine the interplay of HP1α, HP1β and HP1γ with RNAPII. We find that, in the absence of stimulation, HP1β is present on the promoter together with the non‐processive RNAPII and functions as a negative regulator. On activation, HP1β bound to methylated H3K9 is rapidly released concurrent with histone H3 phospho‐acetylation, and is replaced by HP1γ. This isoform localizes to the promoter but also inside the coding region, together with the processive RNAPII. Our data show that HP1 recruitment–release is a sequential mechanism that is precisely regulated and highly dependent on transcription.