The histone variant macroH2A interferes with transcription factor binding and SWI/SNF nucleosome remodeling.
The unusual histone variant macroH2A (mH2A) has been associated with repression of transcription, but the molecular mechanisms by which it exerts this function are unknown. Here we have identified a mechanism by which the different domains of mH2A may be involved in the repression of transcription. Evidence is presented that the presence of mH2A in a positioned nucleosome interferes with the binding of the transcription factor NF-kappaB. The nonhistone region of mH2A was identified to be associated with this interference. Importantly, the presence of macroH2A was found to severely impede SWI/SNF nucleosome remodeling and movement to neighboring DNA segments. This property of mH2A was demonstrated to reside only in its H2A-like domain. A hypothesis explaining the role of histone variants in transcriptional regulation is proposed.
Angelov
Dimitar
D
Ecole Normale Supérieure de Lyon, CNRS-UMR 5665, 46 Allée d'Italie, France.
Molla
Annie
A
Perche
Pierre-Yves
PY
Hans
Fabienne
F
Côté
Jacques
J
Khochbin
Saadi
S
Bouvet
Philippe
P
Dimitrov
Stefan
S
D000818:Animals; D001665:Binding Sites / Q000235:genetics; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism*; D005057:Eukaryotic Cells / Q000378:metabolism*; D005809:Genes, Regulator / Q000235:genetics; D006657:Histones / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D009707:Nucleosomes / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D002868:Chromosomal Proteins, Non-Histone; D006657:Histones; D016328:NF-kappa B; D009707:Nucleosomes; D012097:Repressor Proteins; C445179:SWI-SNF-B chromatin-remodeling complex; D014157:Transcription Factors; C120756:macroH2A histone