Petersen J, Paris J, Willer M, Philippe M, Hagan I M
School of Biological Sciences, 2.205 Stopford Building, University of Manchester, Stopford Building, Oxford Road, Manchester M13 9PT, UK.
J Cell Sci. 2001 Dec;114(Pt 24):4371-84. doi: 10.1242/jcs.114.24.4371.
Metazoans contain three aurora-related kinases. Aurora A is required for spindle formation while aurora B is required for chromosome condensation and cytokinesis. Less is known about the function of aurora C. S. pombe contains a single aurora-related kinase, Ark1. Although Ark1 protein levels remained constant as cells progressed through the mitotic cell cycle, its distribution altered during mitosis and meiosis. Throughout G2 Ark1 was concentrated in one to three nuclear foci that were not associated with the spindle pole body/centromere complex. Following commitment to mitosis Ark1 associated with chromatin and was particularly concentrated at several sites including kinetochores/centromeres. Kinetochore/centromere association diminished during anaphase A, after which it was distributed along the spindle. The protein became restricted to a small central zone that transiently enlarged as the spindle extended. As in many other systems mitotic fission yeast cells exhibit a much greater degree of phosphorylation of serine 10 of histone H3 than interphase cells. A number of studies have linked this modification with chromosome condensation. Ark1 immuno-precipitates phosphorylated serine 10 of histone H3 in vitro. This activity was highest in mitotic extracts. The absence of the histone H3 phospho-serine 10 epitope from mitotic cells in which the ark1(+) gene had been deleted (ark1.Delta1); the inability of these cells to resolve their chromosomes during anaphase and the co-localisation of this phospho-epitope with Ark1 early in mitosis, all suggest that Ark1 phosphorylates serine 10 of histone H3 in vivo. ark1.Delta1 cells also exhibited a reduction in kinetochore activity and a minor defect in spindle formation. Thus the enzyme activity, localisation and phenotype arising from our manipulations of this single fission yeast aurora kinase family member suggest that this single kinase is executing functions that are separately implemented by distinct aurora A and aurora B kinases in higher systems.
后生动物含有三种与极光相关的激酶。极光A是纺锤体形成所必需的，而极光B是染色体浓缩和胞质分裂所必需的。关于极光C的功能了解较少。粟酒裂殖酵母含有一种与极光相关的激酶，即Ark1。尽管随着细胞进入有丝分裂细胞周期，Ark1蛋白水平保持恒定，但其分布在有丝分裂和减数分裂期间发生了变化。在整个G2期，Ark1集中在一到三个与纺锤极体/着丝粒复合体无关的核焦点中。进入有丝分裂后，Ark1与染色质结合，尤其集中在几个位点，包括动粒/着丝粒。在后期A期间，动粒/着丝粒的结合减少，之后它沿着纺锤体分布。该蛋白局限于一个小的中央区域，随着纺锤体延伸，该区域会短暂扩大。与许多其他系统一样，有丝分裂的裂殖酵母细胞比间期细胞表现出更高程度的组蛋白H3丝氨酸10磷酸化。许多研究将这种修饰与染色体浓缩联系起来。Ark1在体外免疫沉淀组蛋白H3的磷酸化丝氨酸10。这种活性在有丝分裂提取物中最高。在缺失ark1(+)基因的有丝分裂细胞（ark1.Delta1）中不存在组蛋白H3磷酸化丝氨酸10表位；这些细胞在后期无法分离其染色体，以及该磷酸化表位在有丝分裂早期与Ark1的共定位，所有这些都表明Ark1在体内使组蛋白H3的丝氨酸10磷酸化。ark1.Delta1细胞还表现出动粒活性降低和纺锤体形成的轻微缺陷。因此，我们对这个单一的裂殖酵母极光激酶家族成员的操作所产生的酶活性、定位和表型表明，这个单一的激酶正在执行在高等系统中由不同的极光A和极光B激酶分别执行的功能。
