Molecular biology of microtuble-interacting proteins

描述(申请人提供)：项目摘要：在动物和真菌细胞中，极微管组织中心(PMTOCs)，如中心体和纺锤体，在微管组装成核中具有公认的作用。然而，最近的数据表明，PMTOCs在有丝分裂和细胞周期的调节中还有其他重要的作用。尽管这一领域显然很重要，但到目前为止所获得的大多数结果都是描述性的，关于PMTOCs参与有丝分裂调控的机制的信息有限。γ-微管蛋白是一种PMTOC蛋白，在微管成核过程中起着关键作用。在目前的赠款期间，我们研究了真菌nidulans的伽马微管蛋白突变的影响，这种突变在特定温度下抑制生长，但不阻止微管组装。我们的结果显示，这些伽马微管蛋白突变破坏了晚期有丝分裂事件的协调，染色体分离，染色体向有丝分裂器官的极点移动，以及有丝分裂退出。此外，我们的数据表明，这些不是微管组装不充分或微管与PMTOCs弱附着的结果。我们认为，这些突变提供了有价值的工具，使我们能够开始研究伽马微管蛋白，进而，PMTOCs参与有丝分裂调控的机制。在当前的授权期内，我们建议确定这些突变体改变了哪些有丝分裂调控通路，以及它们是如何改变的。我们假设有丝分裂调节蛋白与PMTOCs的结合对于它们的功能是重要的，并且伽马微管蛋白突变体可能改变这些蛋白中的一个或多个的结合。因此，我们将研究有丝分裂调节蛋白在有丝分裂中的定位模式。根据这些数据，我们希望能够确定伽马微管蛋白在有丝分裂调节中的作用机制。相关：正确的染色体分离对所有多细胞生物体的细胞繁殖和发育至关重要。不正确的染色体分离会导致出生缺陷和细胞从正常到癌变。曲霉菌的致病种类是免疫功能低下患者死亡的主要原因。

DESCRIPTION (provided by applicant): Project Summary: Polar Microtubule organizing centers (PMTOCs) such as the centrosome and spindle pole body have a well-established role in the nucleation of microtubule assembly in animal and fungal cells. Recent data have suggested, however, that PMTOCs have additional essential roles in the regulation of mitosis and the cell cycle. Although this area is clearly important, most of the results obtained to date are descriptive, and information as to the mechanisms by which PMTOCs participate in mitotic regulation is limited. gamma-Tubulin is a PMTOC protein that plays a critical role in microtubule nucleation. In the current grant period we have studied the effects of gamma-tubulin mutations in the fungus Aspergillus nidulans that inhibit growth at certain temperatures but do not block microtubule assembly. Our results reveal that these gamma- tubulin mutations disrupt the coordination of late mitotic events, chromosomal disjunction, movement of chromosomes to the poles of the mitotic apparatus, and mitotic exit. Our data demonstrate, moreover, that these are not consequences of inadequate microtubule assembly or weak attachment of microtubules to PMTOCs. We believe that these mutations provide valuable tools that allow us to begin to study the mechanisms by which gamma-tubulin and, by extension, PMTOCs participate in mitotic regulation. In the current grant period, we propose to determine which mitotic regulatory pathways are altered by these mutants and how they are altered. We hypothesize that binding of mitotic regulatory proteins to PMTOCs is important for their functioning and that gamma-tubulin mutants may alter the binding of one or more of these proteins. We will, consequently, examine the localization patterns of mitotic regulatory proteins in mitosis. From these data, we expect to be able to determine the mechanisms by which gamma-tubulin functions in mitotic regulation. Relevance: Correct segregation of chromosomes is essential for cellular reproduction and development of all multicellular organisms. Incorrect chromosomal segregation contributes to birth defects and the progression of cells from normal to cancerous. Pathogenic species of Aspergillus are a major cause of mortality in immune-compromised patients.