Histone variant macroH2A1.2 is mono-ubiquitinated at its histone domain

• Published in: Biochemical and biophysical research communications Vol. 336; no. 1; pp. 204 - 209
• Main Authors: Ogawa, Y., Ono, T., Wakata, Y., Okawa, K., Tagami, H., Shibahara, K-i.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 14.10.2005
• Subjects: Amino Acid Sequence; Blotting, Western; Chromatography, Affinity; Electrophoresis, Polyacrylamide Gel; Facultative heterochromatin; HeLa Cells; Histone macroH2A; Histone modification; Histone variants; Histones - chemistry; Histones - isolation & purification; Histones - metabolism; Humans; Molecular Sequence Data; Mono-ubiquitination; Nucleosomes - metabolism; Sequence Homology, Amino Acid; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Ubiquitin - metabolism; Mono-ubiquitination; Histone macroH2A; Histone modification; Histone variants; Facultative heterochromatin
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2005.08.046

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.