Abstract
Mitotic phosphorylation of histone H3 is considered to play a crucial role in chromosome condensation and segregation. Aurora kinase is a major enzyme responsible for phosphorylation of histone H3 at Ser10 and Ser28. When mammalian cells were treated with an Aurora kinase inhibitor, Hesperadin, phosphorylation of histone H3 at Ser10 was inhibited and chromosomes failed to segregate. In this study, we investigated roles of histone H3 phosphorylation in plants using Hesperadin. We performed indirect immunofluorescent staining using anti-phosphorylated histone H3 antibodies in tobacco BY-2 cultured cells treated with Hesperadin. Hesperadin prevented the phosphorylation of histone H3 at Ser10 and Ser28, while has no effect on the localization of phosphorylated histone H3 at Thr3 and Thr11, as well as on chromosome condensation. These results suggest that phosphorylation of histone H3, not at Ser10 and Ser28 but at Thr3 and Thr11, would have a functional role for chromosome condensation in plants.
