CENTROSOME ASSEMBLY IN C ELEGANS EMBRYOS

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 中心粒是一种细胞器，在纤毛和鞭毛的形成中起重要作用，参与胞质分裂、细胞周期控制和中心体组织。细胞的单个中心体作为纺锤极遗传，每个细胞周期只复制一次，这一过程是通过控制中心粒复制来调节的。严格控制中心粒复制，确保两极纺锤体的形成和倍性的保持。多年来，人们已经知道，女儿的中心粒与年长的中心粒或“母亲”中心粒成直角聚集。这一现象的意义以及子代中心粒组装的途径仍然是个谜。我们正在使用相关的光和EM断层扫描方法来研究线虫分期胚胎中的中心体组装。我们的初步结果表明，这种生物体中的子代中心粒组装始于中央管的形成，就像秀丽线虫的原核出现时(Pelletier，L.，O‘Toole，E.T.，Schwager，A.，Hyman，A.A.和M？ler-Reichert，T.(2006))中心粒组装。自然444,619-23)。中央管在原核迁移过程中拉长，单线态微管在管上的组装发生在原核旋转过程中。利用EM-CT结合RNA干扰和修复显微镜，我们发现证据表明，管的形成和延长需要SAS-5/SAS-6蛋白和由Spd-2和Zyg-1介导的上游信号。我们进一步表明，虽然中心管的组装仍然发生，但在没有SAS-4的情况下，单线态微管不能组装，这表明在组装步骤中特别需要它。我们在线虫中描述的中心粒组装途径可能为进一步研究其他含有中心粒的生物体中的中心粒组装提供一个框架。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. 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.