The role of centrosomes in cell proliferation, division, and development

中心粒通过招募成核和锚定微管的中心粒周围物质来组织中心体。中心体反过来又指导细胞内聚焦微管阵列的组装。虽然中心体在100多年前被发现，但中心体对细胞增殖、分裂和发育的贡献仍然是当前研究的一个重要课题。我的赞助实验室最近开发了一种Plk4激酶抑制剂，它控制着新的中心粒的形成。用这种称为中心体酮的抑制剂处理细胞，可以使脊椎动物细胞中的中心体耗竭。我的项目旨在使用中心体酮作为工具来阐明中心体在细胞增殖，分裂和发育中的作用。在我的赞助实验室的工作表明，正常细胞具有p53依赖的传感器，可以检测中心体丢失并阻止G1中的细胞，而缺乏完整p53途径的转化细胞继续增殖。本提案的第一个目标是了解细胞感知中心体丢失能力的分子机制。因此，我将根据我们目前对中心体结构和组成的了解，利用功能方法来了解中心体丢失是如何导致p53激活的。第二个目标建立在我的初步发现之上，即中心体的去除不会明显改变后期细胞中星状微管阵列的结构。在这里，我想了解当中心体缺失时星体微管阵列是如何形成的，并利用这些信息来研究星体微管在细胞分裂期间收缩环蛋白皮质积累中的作用。在第三个目标中，我将以人类胚胎干细胞为模型，分析中心体和星状微管在发育过程中对纺锤体取向的作用。特别是，我计划确定中心体和NuMA/LGN/Gai通路如何促进wnt介导的纺锤体取向。综上所述，本研究将利用中心体酮作为一种工具来研究中心体在发育过程中增殖能力、确定分裂平面和极化细胞分裂中的作用。

Centrioles organize centrosomes by recruiting pericentriolar material that nucleates and anchors microtubules. Centrosomes, in turn, direct the assembly of focal microtubule arrays in cells. Although discovered over 100 years ago, the contribution of centrosomes to cell proliferation, cell division, and development remains an important topic of current research. My sponsor lab recently developed an inhibitor of the kinase Plk4, which controls new centriole formation. Treatment of cells with this inhibitor, called centrinone, allows depletion of centrosomes from vertebrate cells. My project aims to use centrinone as a tool to shed light on the role of centrosomes in cell proliferation, division and development. Work in my sponsor lab has shown that normal cells possess a p53 dependent sensor that detects centrosome loss and arrests cells in G1, whereas transformed cells lacking an intact p53 pathway continue to proliferate. The goal of the first aim of this proposal is to understand the molecular mechanisms underlying the ability of cells to sense centrosome loss. Therefore, I will take utilize a functional approach based on our current understanding of centrosome structure and composition to understand how centrosome loss leads to p53 activation. The second aim builds on my preliminary finding that centrosome removal does not apparently alter the structure of the astral microtubule arrays in anaphase cells. Here I would like to understand how astral microtubule arrays form when centrosomes are absent and to use this information to study the role of astral microtubules in patterning the cortical accumulation of contractile ring proteins during cytokinesis. In the third aim, I will use human embryonic stem cells as a model to analyze the role of centrosomes and astral microtubules in spindle orientation during development. In particular, I plan to determine how centrosomes and the NuMA/LGN/Gai pathway contribute to Wnt-mediated spindle orientation. In summary, the proposed work will capitalize on the availability of centrinone as a tool to investigate the role of centrosomes in competence for proliferation, defining the division plane, and in polarized cell divisions during development.