Histone Variant macroH2A1.2 Is Mono-Ubiquitinated at Its Histone Domain

Biochem Biophys Res Commun. 2005 Oct 14;336(1):204-9. doi: 10.1016/j.bbrc.2005.08.046.

Abstract

Histone macroH2A1.2 (macroH2A) is an unusual histone H2A variant with a large non-histone macrodomain at its carboxyl terminal. MacroH2A1.2 is enriched in facultative heterochromatin, including inactivated X chromosomes in mammalian females and senescence-associated heterochromatin foci. We show here that a small population of macroH2A1.2 is mono-ubiquitinated in human HeLa cells. Mass spectrometry analysis revealed that the specific targeting sites for the mono-ubiquitination are Lys115 and Lys116 of the histone domain. A corresponding Lys119 conserved in histone H2A is also mono-ubiquitinated by Ring protein in the polycomb group complex. We suggest that the mono-ubiquitination of macroH2A1.2 and histone H2A has similar or synergistic implications, but that the multiple ubiquitination sites in macroH2A1.2 might confer a variety of functions upon macroH2A1.2 to modulate chromatin states.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Blotting, Western
  • Chromatography, Affinity
  • Electrophoresis, Polyacrylamide Gel
  • HeLa Cells
  • Histones / chemistry
  • Histones / isolation & purification
  • Histones / metabolism*
  • Humans
  • Molecular Sequence Data
  • Nucleosomes / metabolism
  • Sequence Homology, Amino Acid
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
  • Ubiquitin / metabolism*

Substances

  • Histones
  • Nucleosomes
  • Ubiquitin
  • macroH2A histone