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Mol Cell Biol 2006 Feb 01;263:1156-64. doi: 10.1128/MCB.26.3.1156-1164.2006.
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Mechanism of polymerase II transcription repression by the histone variant macroH2A.

Doyen CM , An W , Angelov D , Bondarenko V , Mietton F , Studitsky VM , Hamiche A , Roeder RG , Bouvet P , Dimitrov S .

macroH2A (mH2A) is an unusual histone variant consisting of a histone H2A-like domain fused to a large nonhistone region. In this work, we show that histone mH2A represses p300- and Gal4-VP16-dependent polymerase II transcription, and we have dissected the mechanism by which this repression is realized. The repressive effect of mH2A is observed at the level of initiation but not at elongation of transcription, and mH2A interferes with p300-dependent histone acetylation. The nonhistone region of mH2A is responsible for both the repression of initiation of transcription and the inhibition of histone acetylation. In addition, the presence of this domain of mH2A within the nucleosome is able to block nucleosome remodeling and sliding of the histone octamer to neighboring DNA segments by the remodelers SWI/SNF and ACF. These data unambiguously identify mH2A as a strong transcriptional repressor and show that the repressive effect of mH2A is realized on at least two different transcription activation chromatin-dependent pathways: histone acetylation and nucleosome remodeling.

PubMed ID: 16428466
PMC ID: PMC1347033
Article link: Mol Cell Biol

Species referenced: Xenopus laevis
Genes referenced: a1cf crebbp h2ac21 lgals4.2 macroh2a1

References [+] :
Allen, The crystal structure of AF1521 a protein from Archaeoglobus fulgidus with homology to the non-histone domain of macroH2A. 2003, Pubmed