Control of mammalian meiosis I through protein kinase signaling

描述(由申请人提供)：减数分裂I(MI)期间的染色体分离是独特的，因为同源染色体对是分离的。在人类中，MI的错误发生在女性配子(卵母细胞)中的比例高得惊人，导致不孕、流产或出生缺陷。控制心肌梗死的分子机制还知之甚少。这项提案的目标是剖析Aurora B和Aurora C蛋白激酶控制MI的机制，以解释这一现象。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，而Aurora活性是完成正常MI分离所必需的。极光C激酶(AURKC)在配子中的表达高度上调。然而，由于AURKC与Aurora B激酶(AURKB)有很高的序列同源性，了解其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包含两个彼此相似的激酶的谜团，并鉴定了小鼠卵母细胞在MI期间的AURKC功能，这与AURKB不同。这些功能包括确保染色体在中期I平板上的正常排列和染色体分离，通过控制不正确的微管连接到染色体来维持适当的染色体数量。在这项建议中，我们的目标是充分确定AURKB和AURKC的MI功能。我们已经产生了卵母细胞中缺乏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。这一策略将在目标1中用于研究AURKB和AURKC在心肌梗死期间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，即一些功能是不同的，而其他功能是重叠的。我们已经证明AURKC在中期I的染色体臂上有一个独特的定位，这在有丝分裂中期是没有的。在目标2中，我们开发了干扰AURKC在轴上的定位活性的策略，以验证这一假设，该定位的AURKC活性控制着MI期间的减数分裂染色体凝聚。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心肌梗死期间是如何运作的，同时强调有丝分裂和心肌梗死如何控制之间的明显差异。重要的是，这些数据将阐明在卵母细胞中MI染色体分离是如何控制的，以及为什么它在女性中经常出现错误，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.