title: Higher concentrations of histone macroH2A in the Barr body are correlated with higher nucleosome density.
abstract: Histone macroH2A, which is a subtype of histone H2A, possesses a histone H2A-like portion fused to a relatively long non-histone portion. MacroH2A has been shown to associate preferentially with the inactive X chromosome [1]. To investigate the specificity of this association, the nuclear distribution of macroH2A was compared with that of regular core histones. In normal human female fibroblasts, all anti-histone antibodies that were tested (including anti-macroH2A antibody) preferentially labeled the inactive X chromosome. Moreover, when expressed as green fluorescent protein (GFP) fusions, both histone H2A and macroH2A were concentrated in the Barr body. These data clearly show the presence of a higher density of nucleosomes in the inactive X chromosome. Accordingly, the specificity of the macroH2A association with the inactive X chromosome should be reconsidered. While investigating the role of macroH2A, we found that the proximity of the non-histone region of macroH2A to a promoter could lead to a specific repression of transcription, suggesting that the incorporation of macroH2A into chromatin might help to establish the stable pattern of gene expression in differentiated cells.
authors: Equipe, DyOGen, Institut Albert Bonniot, Faculté de Médecine, et Laboratoire de Biologie Moléculaire et Cellulaire de la Différenciation, INSERM U309, Domaine de la Merci, 38706,., La Tronche Cedex, France.
authors: P Y
authors: PY
authors: Perche
authors: C
authors: C
authors: Vourc'h
authors: L
authors: L
authors: Konecny
authors: C
authors: C
authors: Souchier
authors: M
authors: M
authors: Robert-Nicoud
authors: S
authors: S
authors: Dimitrov
authors: S
authors: S
authors: Khochbin
mesh_terms: D005260:Female; D005347:Fibroblasts; D006657:Histones / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D009707:Nucleosomes / Q000378:metabolism*; D015347:RNA Probes; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012728:Sex Chromatin / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014960:X Chromosome / Q000378:metabolism*
chemical_list: D006657:Histones; D009707:Nucleosomes; D015347:RNA Probes; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; C077885:XIST non-coding RNA; C120756:macroH2A histone