DYNAMICS OF CENTROSOME-MICROTUBULE ASSOCIATION

母提案的总体目标是了解 体内微管动力学及其与动态活动的关系 和重要的细胞生物学功能，包括组织 细胞质、细胞形态的产生、细胞分裂和细胞运动。这个 作为父提案基础的概念框架是 微管及其在细胞内的周转是细胞内相互作用的结果 组件。两类重要的成分是：(1)中心体作为 成核和锚定结构；(2)影响成核和锚定的细胞质因素 分别为负数和正数的动态活动。特别关注 在父母的提案中将有一个新奇的，最近形成的假设 他们称之为“负端通路”的微管周转。 在本申请中，调查人员提议探索一个相关问题。一个 微管动力学领域中的悖论是微管与微管之间的明显矛盾 快速的微管翻转和缓和的正端动态不稳定性。 实验分析和理论计算表明，回火后的 动力不稳定不能解释快速形成和周转 微管长达几十微米，常见于各种细胞中。 调查人员认为，这种差异是由不完整的 对观察受限导致的微管行为的理解 到细胞外围，而内部细胞质的行为保持不变 基本上是未知的。需要检验的具体假设是“持续性” 微管形成和更新的“生长”模型。根据这一观点， 从中心体释放的微管从其负端解聚并 被在中心体上成核的微管取代，这些微管通过 向细胞边缘连续伸长。只有在单元格边缘附近才有 微管表现出一种称为动态不稳定性的随机随机行为。 使用数字荧光显微镜的新方法将被开发为 获取细胞内部微管行为的数据。

The broad objectives of the Parent Proposal are to understand the mechanism of microtubule dynamics in vivo and the relationship between this dynamic activity and important cell biological functions including organization of the cytoplasm, the generation of cell form, cell division, and cell locomotion. The conceptual framework underlying the Parent Proposal is that the organization of microtubules and their turnover in cells result from an interplay of cellular components. Two important classes of component are: (1) the centrosome as a nucleating and anchoring structure and (2) cytoplasmic factors that effect the dynamic activity of the minus and plus ends, respectively. Of particular focus in the Parent Proposal will be a novel, recently formulated hypothesis for microtubule turnover which they call the "minus-end pathway." In this application, the investigators propose to explore a related issue. A paradox in the microtubule dynamics field is the apparent contradiction between rapid microtubule turnover and tempered dynamic instability of plus ends. Experimental analysis and theoretical calculations indicate that tempered dynamic instability can not account for the rapid formation and turnover of microtubules tens of micrometers long commonly observed in a variety of cells. The investigators suggest that this discrepancy results from an incomplete understanding of microtubule behavior resulting from observations being limited to the cell periphery while behavior in the internal cytoplasm remains essentially unknown. The specific hypothesis to be tested is the "persistent growth" model for microtubule formation and turnover. According to this view, microtubules released from the centrosome depolymerize from their minus end and are replaced by microtubules nucleated at the centrosome which grow by continuous elongation towards the cell margin. Only near the cell margin do microtubules display the random stochastic behavior termed dynamic instability. Novel methods employing digital fluorescence microscopy will be developed to obtain data on microtubule behavior in the cell interior.