Mechanisms of chromosome segregation and mitotic timing

 描述（由申请人提供）：本提案旨在研究动粒蛋白捕获微管以确保染色体分离均等和有丝分裂及时进展的机制。通过分析纺锤体相关的含层粘连蛋白B的网络，我们以前称之为纺锤体基质，我们已经做出了一些令人兴奋的观察，这表明层粘连蛋白B网络的组分与微管一起作为动粒蛋白如Bub3的伴侣蛋白发挥作用。这些分子伴侣是着丝粒蛋白调节适当的微管和着丝粒相互作用和及时的有丝分裂进程所必需的。我们建议剖析这些分子伴侣在有丝分裂中发挥作用的分子机制。具体来说，在目标1中，我们将剖析BuGZ和微管和/或EB 1之间的相互作用是否以及如何需要Bub3动粒加载和染色体比对。在目的2中，我们将研究RanGTP对BuGZ和Bub3的不稳定是否有助于纺锤体组装检查点（SAC）的沉默。在目标3中，我们提出研究介导末端着丝粒-MT附着和SAC沉默的分子机制。

 DESCRIPTION (provided by applicant): This proposal aims to study the mechanism by which kinetochore proteins capture microtubules to ensure equal chromosome segregation and timely progression through mitosis. Through analyzing the spindle-associated lamin-B containing network, which we had referred to as the spindle matrix previously, we have made a number of exciting observations, which suggest that component(s) of the lamin-B network functions together with microtubules as chaperones for kinetochore proteins such as Bub3. These chaperones are required for kinetochore proteins to regulate proper microtubule and kinetochore interactions and timely mitosis progression. We propose to dissect the molecular mechanism by which these chaperones function in mitosis. Specifically, in Aim 1 we will dissect whether and how the interaction between BuGZ and microtubules and/or EB1 is required for Bub3 kinetochore loading and chromosome alignment. In Aim 2 we will study whether the destabilization of BuGZ and Bub3 by RanGTP contributes to silencing of the spindle assembly checkpoint (SAC). In Aim 3, we propose to study the molecular mechanisms that mediate end-on kinetochore-MT attachment and SAC silencing.