Identification of a Novel Phosphorylation Site on Histone H3 Coupled with Mitotic Chromosome Condensation

作者：Hidemasa Goto, Hidetaka Kosako, Yasuko Tomono, Kozo Ajiro, Masatoshi Fujita, Minoru Sakurai, Katsuya Okawa, Akihiro Iwamatsu, Tohru Okigaki, Toshitada Takahashi, Masaki Inagaki · 发表于：Journal of Biological Chemistry · 年份：1999 · DOI：10.1074/jbc.274.36.25543 · 被引用次数：461 · 研究领域：Genomics and Chromatin Dynamics、RNA Research and Splicing、RNA and protein synthesis mechanisms

Histone H3 (H3) phosphorylation at Ser(10) occurs during mitosis in eukaryotes and was recently shown to play an important role in chromosome condensation in Tetrahymena. When producing monoclonal antibodies that recognize glial fibrillary acidic protein phosphorylation at Thr(7), we obtained some monoclonal antibodies that cross-reacted with early mitotic chromosomes. They reacted with 15-kDa phosphoprotein specifically in mitotic cell lysate. With microsequencing, this phosphoprotein was proved to be H3. Mutational analysis revealed that they recognized H3 Ser(28) phosphorylation. Then we produced a monoclonal antibody, HTA28, using a phosphopeptide corresponding to phosphorylated H3 Ser(28). This antibody specifically recognized the phosphorylation of H3 Ser(28) but not that of glial fibrillary acidic protein Thr(7). Immunocytochemical studies with HTA28 revealed that Ser(28) phosphorylation occurred in chromosomes predominantly during early mitosis and coincided with the initiation of mitotic chromosome condensation. Biochemical analyses using (32)P-labeled mitotic cells also confirmed that H3 is phosphorylated at Ser(28) during early mitosis. In addition, we found that H3 is phosphorylated at Ser(28) as well as Ser(10) when premature chromosome condensation was induced in tsBN2 cells. These observations suggest that H3 phosphorylation at Ser(28), together with Ser(10), is a conserved event and is likely to be involved in mitotic chromosome condensation.