Control of mammalian meiosis I through protein kinase signaling

描述（由申请方提供）：减数分裂I（MI）期间的染色体分离是独特的，因为同源染色体对分离。在人类中，MI的错误发生在女性配子（卵母细胞）中的比例非常高，导致不育，流产或出生缺陷。控制MI的分子机制知之甚少。本提案的目标是着重于剖析极光B和极光C蛋白激酶用于控制MI的机制，以解释这种现象。Aurora蛋白激酶家族是有丝分裂中染色体分离的重要调节因子，Aurora活性是完成正常MI分离所必需的。极光C激酶（AURKC）的表达在配子中高度上调.然而，由于AURKC与极光B激酶（AURKB）具有高度的序列同源性，因此理解其MI特异性功能的标准方法是不够的。我们已经开始解开为什么卵母细胞含有2种彼此相似的激酶的谜团，并且已经确定了小鼠卵母细胞MI期间AURKC的功能不同于AURKB。这些功能包括确保中期I平板上正常的染色体排列和染色体分离，以通过控制不正确的微管附着到染色体上来维持正确的染色体数目。在这个建议中，我们的目标是完全确定的MI功能的AURKB和AURKC。我们已经产生了在卵母细胞中缺乏Aurkb和Aurkc的小鼠，以使用化学遗传学策略对AURK功能进行更彻底的分析。本研究将在目的1中探讨AURKB和AURKC在MI过程中微管动力学和胞质分裂中的分子机制。这一目标将检验这样一个假设，即某些功能是不同的，而另一些功能是重叠的。我们已经证明，AURKC有一个独特的定位沿着染色体臂在染色单体间轴在中期I，是没有发现在有丝分裂中期。在目标2中，我们开发的策略，扰乱本地化的AURKC的活动在轴测试的假设，本地化的AURKC活动控制减数分裂染色体浓缩MI。从我们的研究中获得的信息将帮助我们充分了解这些激酶在MI期间如何运作，同时突出有丝分裂和MI之间的明显差异。重要的是，这些数据将揭示MI染色体分离是如何在卵母细胞中控制的，以及为什么它在女性中通常会出错，导致染色体分离错误。

DESCRIPTION (provided by applicant): Chromosome segregation during meiosis I (MI) is unique because homologous chromosome pairs segregate. In humans, mistakes in MI occur are strikingly high in female gametes (oocytes), resulting in infertility, miscarriage, or birth defects. The molecular mechanisms that control MI are poorly understood. The goal of this proposal is focused on dissecting the mechanisms that the Aurora B and Aurora C protein kinases use to control MI to explain this phenomenon. The Aurora protein kinase family is an essential regulator of chromosome segregation in mitosis, and Aurora activity is required for completing a normal MI segregation. Aurora C kinase (AURKC) expression is highly up- regulated in gametes. Yet, because AURKC shares high sequence homology with Aurora B kinase (AURKB) standard approaches to understand their MI-specific functions are not sufficient. We have begun to unravel the mystery of why oocytes contain 2 kinases that are similar to one another, and have identified AURKC functions during MI in mouse oocytes that are distinct from AURKB. These functions include ensuring normal chromosome alignment at the metaphase I plate and chromosome segregation to maintain proper chromosome numbers through controlling incorrect microtubule attachments to chromosomes. In this proposal, we aim to fully determine the MI functions of both AURKB and AURKC. We have generated mice that lack Aurkb and Aurkc in their oocytes to conduct more thorough analyses of AURK function using a chemical genetics strategy. This strategy will be used in Aim 1 to investigate the molecular mechanisms of AURKB and AURKC in microtubule dynamics and cytokinesis during MI. This aim will test the hypothesis that some functions are distinct, whereas other functions are overlapping. We have demonstrated that AURKC has a unique localization along chromosome arms at the interchromatid axes during metaphase I that is not found in mitotic metaphase. In Aim 2 we develop strategies to perturb the localized activity of AURKC at the axes to test the hypothesis this localized AURKC activity controls meiotic chromosome condensation during MI. Information gained from our studies will help us fully understand how these kinases operate during MI while highlighting distinct differences between how mitosis and MI are controlled. Importantly, these data will shed light on how MI chromosome segregation is controlled in oocytes and why it commonly goes awry in women leading to chromosome segregation errors.