CENTROSOME ASSEMBLY IN C ELEGANS EMBRYOS

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 中心粒是在纤毛和鞭毛的形成中起重要作用的细胞器，它们参与胞质分裂、细胞周期控制和中心体组织。细胞的单个中心体，遗传为纺锤体，每个细胞周期仅复制一次，这是通过控制中心粒复制来调节的过程。严格控制中心粒重复以确保形成双极纺锤体和维持倍性。多年来，人们已经知道，子中心粒与老中心粒或“母亲”中心粒成直角聚集。这一现象的意义以及子中心粒的组装途径仍然是个谜。我们正在使用相关光和EM断层扫描的方法来研究C期的中心体组装。线虫胚胎我们的初步结果表明，在这种生物体中，子中心粒的组装开始于中心管的形成，就像原核出现一样（Pelletier，L.，奥图尔外星人Schwager，A.，海曼，A.A.，和M？ller-Reichert，T. 2006年，《秀丽隐杆线虫Centriole assembly in Caesarhabditis elegans》。Nature 444，619-23）。在原核迁移过程中，中心管伸长，在原核旋转过程中，中心管上的单线态微管发生组装。使用EM-断层扫描结合RNA干扰和恢复显微镜，我们发现的证据表明，管的形成和伸长需要SAS-5/SAS-6蛋白和上游信号介导的SPD-2和ZYG-1。我们进一步表明，虽然组装的中心管仍然发生，单线态微管未能组装在SAS-4的情况下，这表明它是专门需要在该步骤的组装。我们在C. elegans可能为进一步研究其他中心粒生物的中心粒组装提供了一个框架。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Centrioles are organelles that play essential roles in the formation of cilia and flagella, and they participate in cytokinesis, cell cycle control and centrosome organization. The cell's single centrosome, which is inherited as a spindle pole, duplicates only once per cell cycle, a process that is regulated through the control of centriole duplication. Centriole duplication is strictly controlled to ensure the formation of a bipolar spindle and the maintenance of ploidy. It has been known for many years that daughter centrioles assemble at right angles to the older, or "mother" centriole. The significance of this and the pathway for daughter centriole assemble remain mysterious. We are using the correlative light and EM tomography approach to study centrosome assembly in staged C. elegans embryos. Our initial results showed that daughter centriole assembly in this organism begins with the formation of a central tube, just as the pronuclei appear (Pelletier, L., O'Toole, E.T., Schwager, A., Hyman, A.A., and M¿ller-Reichert, T. (2006) Centriole assembly in Caenorhabditis elegans. Nature 444, 619-23). The central tube elongates during pronuclear migration, and the assembly of singlet microtubules on the tube occurs during pronuclear rotation. Using EM-tomography in combination with RNA interference and restoration microscopy we have found evidence suggesting that tube formation and elongation requires the SAS-5/SAS-6 proteins and an upstream signal mediated by SPD-2 and ZYG-1. We further show that although the assembly of the central tube still occurs, singlet microtubules fail to assemble in the absence of SAS-4, suggesting that it is required specifically at that step of assembly. The centriole assembly pathway we describe here in C. elegans may provide a framework for further studies on centriole assembly in other centriole bearing organisms.