Specialized distribution of the histone methyltransferase Ezh2 in the nuclear apical region of round spermatids and its interaction with the histone variant H1t2.
The formation of sperm requires tightly regulated gene expression and  unique chromatin remodeling. In the present study, we investigated the  spermatogenic distribution of the lysine-specific histone H3 methyltransferase  Ezh2 in mice. The distribution of Ezh2 was highly regulated with its  localization predominantly restricted to round spermatids in the perinuclear  acrosome region. This localization is concomitant with the dramatic epigenetic  reorganization that occurs during spermiogenesis leading to an extreme  compaction of the chromatin. Spermiogenesis involves the incorporation of  sperm-specific nuclear proteins, including the testis-specific histone variant  H1t2. Using immunofluorescence, Ezh2 was shown to juxtapose H1t2, and an  interaction in chromatin was confirmed by immunoprecipitation. These findings  suggest that, in the testis, the apical region of the round spermatid nucleus  could be a specialized epigenetic region where methylation of histones serves  a role in the spermiogenic chromatin remodeling and that Ezh2 might be a key  effector of this event.
Department of Animal Science, McGill University, 21111 Lakeshore Rd, Ste-Anne-de-Bellevue, Québec, Canada H9X 3V9.
Romain
R
Lambrot
Steven
S
Jones
Shawna
S
Saint-Phar
Sarah
S
Kimmins
D000818:Animals; D002467:Cell Nucleus / Q000201:enzymology*; D042002:Chromatin Assembly and Disassembly / Q000235:genetics; D047369:Chromatin Immunoprecipitation; D000071221:Enhancer of Zeste Homolog 2 Protein; D044127:Epigenesis, Genetic; D005455:Fluorescent Antibody Technique; D005786:Gene Expression Regulation; D006657:Histones / Q000378:metabolism*; D008297:Male; D051379:Mice; D063151:Polycomb Repressive Complex 2 / Q000378:metabolism*; D021381:Protein Transport; D013087:Spermatids / Q000201:enzymology*; D013091:Spermatogenesis / Q000235:genetics; D013737:Testis / Q000201:enzymology*; D013997:Time Factors
D006657:Histones; D000071221:Enhancer of Zeste Homolog 2 Protein; C498410:Ezh2 protein, mouse; D063151:Polycomb Repressive Complex 2