title: The basic linker of macroH2A stabilizes DNA at the entry/exit site of the nucleosome.
abstract: MacroH2A is a histone H2A variant that is typically found in heterochromatic regions of the genome. A positively charged linker that connects the histone-fold with the macro-domain was suggested to have DNA-binding properties, and has been shown to promote oligomerization of chromatin fibers. Here we examine the influence of this basic linker on DNA of mononucleosomes. We find that the macro-linker reduces accessibility to extranucleosomal DNA, and appears to increase compaction of the nucleosome. These properties arise from interactions between the H1-like basic linker region and DNA around the entry/exit site, which increases protection of nucleosomal DNA from exonuclease III digestion by ∼10 bp. By stabilizing the wrapping of DNA around the histone core, this basic linker of macroH2A may alter the distribution of nucleosome-associated factors, and potentially contribute to the more compacted nature of heterochromatin.
authors: T.C. Jenkins Department of Biophysics, Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218, USA.
authors: Srinivas
authors: S
authors: Chakravarthy
authors: Ashok
authors: A
authors: Patel
authors: Gregory D
authors: GD
authors: Bowman
mesh_terms: D004247:DNA / Q000737:chemistry* / Q000378:metabolism; D006657:Histones / Q000737:chemistry* / Q000378:metabolism; D009707:Nucleosomes / Q000737:chemistry* / Q000378:metabolism; D017434:Protein Structure, Tertiary
chemical_list: D006657:Histones; D009707:Nucleosomes; C120756:macroH2A histone; D004247:DNA