The role of Kin3p in the fidelity of chromosome transmission in Saccharomyces cerevisiae Die Rolle des Kin3p bei der Genauigkeit der Chromosomensegregation in Saccharomyces cerevisiae

在酿酒酵母中，KIN3编码一个丝氨酸/苏氨酸蛋白激酶，该蛋白激酶序列与中性曲霉的nimA和人类基因Nek2具有最高的同源性。虽然nimA在细胞周期g2期到有丝分裂的过渡过程中起着至关重要的作用，但Nek2被认为对中心体的完整性很重要。我们已经能够证明KIN3以细胞周期依赖的方式表达，转录物水平在有丝分裂时达到峰值。它是一个非必需基因，缺失突变不表现出明显的表型。像人类细胞中的Nek2一样，Kin3p定位于纺锤极体附近。鉴于这些结果，我们测试了KIN3缺失是否损害染色体分离。采用染色体片段稳定性测定，我们已经能够表明，Kin3p，与有丝分裂检查点，控制染色体传递的保真度。这些数据表明，Kin3p和Nek2具有相似的功能。为了阐明Kin3p的分子功能，我们计划下一步寻找与该激酶相互作用的蛋白质。研究Kin3p及其相互作用伙伴之间的关系有助于我们了解Kin3p如何在分子水平上起作用，以确保染色体传播的高保真度。

KIN3 codes for a Ser/Thr protein kinase in Saccharomyces cerevisiae which shows highest sequence homology to nimA of Aspergillus nidulans and the human gene Nek2. While nimA plays an essential role in the transition from G2-phase of the cell cycle to mitosis, Nek2 is thought to be important for centrosome integrity. We have been able to show that KIN3 is expressed in a cell cycle dependent manner with transcript levels peaking in mitosis. It is a non-essential gene, and deletion mutants do not show an obvious phenotype. Like Nek2 in human cells Kin3p localises near the spindle pole bodies. In the view of these results we tested whether deleton of KIN3 impairs chromosome segregation. Employing a chromosomal fragment stability assay we have been able to show that Kin3p, in conjunction with the mitotic checkpoint, controls the fidelity of chromosome transmission. These data suggest that Kin3p and Nek2 share similar functions. To elucidate the molecular function of Kin3p we plan next to undertake a search for proteins which interact with this kinase. The study of the relationship between Kin3p and its interaction partners should help us to understand how Kin3p acts on the molecular level to ensure high fidelity of chromosome transmission.