MPS1 KINASE AND YEAST SPINDLE POLE CYCLE

该项目的目标是了解MPS 1的作用 蛋白激酶在S.酿酒酵母纺锤体极体（SPB）复制和 在纺锤体组装检查点中，并确定该激酶是否 在控制中心体复制中广泛保守。 的 有丝分裂和减数分裂纺锤体的形成， 传播依赖于适当的中心体复制， 功能 了解中心体重复将有助于 剖析染色体不分离的机制 不平衡和隐性突变在肿瘤中的表达- 抑制基因 MPS 1基因突变导致SPB复制缺陷， 纺锤体组装检查点途径。 调查人员现在可以 监测分离的Mps 1 p（表位标记）蛋白激酶活性， 酵母在内源水平。 他将用这种试剂来研究 Mps 1 p的激酶活性在细胞周期中受到调节。 分离Mps 1 p两种功能的突变及对Mps 1 p的分析 进行MPS 1 P磷酸化的目的是了解 Mps 1 p如何在细胞周期中发挥其两种作用。 以识别 基因的产物与Mps 1 p相互作用，他们计划确定 不同剂量表型的抑制子过度表达 活性或无催化活性的MPS 1。 这些将被分析， 确定它们如何与MPS 1相互作用，并确定它们在SPB中的作用 复制或主轴装配检查点。 研究人员已经确定了在基因组中 与MPS 1基因突变的组合。 一个他将继续 这项研究是一种新的，必需的MOE 1基因，似乎是必需的， 正常纺锤体功能。 他们也会分离出相应的基因 与他们发现的其他几种合成致命突变有关。 对这些新发现的基因的分子分析应该能表明 编码的基因产物与Mps 1 p相互作用，并证明如果 新基因参与SPB复制或纺锤体检查点。 MPS 1的序列同源物已在多种生物中鉴定。 在小鼠中，一种潜在的同源物由埃斯克基因编码。 他们提出 研究埃斯克在小鼠胚胎中的表达及活性 成纤维细胞 他还将过度表达活跃和不活跃的埃斯克， 小鼠细胞并确定细胞是否表现出指示 中心体复制或纺锤体组装检查点的缺陷。 结果应该表明MPS 1激酶是否编码保守的 在其已知的角色中发挥作用。

The proposed project's goals are to understand the role of the MPS1 protein kinase in S. cerevisiae spindle pole body (SPB) duplication and in the spindle assembly checkpoint, and to determine if this kinase is widely conserved in the control of centrosome duplication. The formation of mitotic and meiotic spindles responsible for chromosome transmission is dependent upon proper centrosome duplication and function. Understanding centrosome duplication will be pertinent to dissecting the mechanisms of nondisjunction involved in chromosome imbalance and in the expression of recessive mutations in tumor- suppressing genes. Mutations in the MPS1 gene cause defects in SPB duplication and the spindle assembly checkpoint pathway. The investigator's are now able to monitor Mps1p (epitope-tagged) protein kinase activity isolated from yeast at endogenous levels. He will use this reagent to study how the kinase activity of Mps1p is regulated during the cell cycle. Mutagenesis to separate the two functions of Mps1p and the analysis of Mps1p phosphorylation will be performed with the goal of understanding how Mps1p executes its two roles during the cell cycle. To identify genes whose products interact with Mps1p, they plan to identify suppressors of the distinct dosage phenotypes of overexpressing either active or catalytically inactive MPS1. These will be analyzed to determine how they interact with MPS1 and to determine their role in SPB duplication or the spindle assembly checkpoint. The investigator's have identified mutations that are inviable in combination with mutations in the MPS1 gene. One he will continue to study is the novel, essential MOE1 gene that appears to be required for normal spindle function. They also will isolate the genes corresponding to several other synthetic lethal mutations they have identified. Molecular analysis of these newly identified genes should indicate how the encoded gene product interacts with Mps1p, and demonstrate if the new genes is involved in SPB duplication or the spindle checkpoint. Sequence homologues of MPS1 have been identified in various organisms. In mice a potential homologue is encoded by the esk gene. They propose to study the expression and activity of esk in mouse embryonic fibroblasts. He also will overexpress both active and inactive esk in mouse cells and determine if the cells exhibit phenotypes indicative of defects in centrosome duplication or the spindle assembly checkpoint. The results should indicate if the MPS1 kinase encodes a conserved function in either of its known roles.