Stemm-Wolf Alexander J, Morgan Garry, Giddings Thomas H, White Erin A, Marchione Robb, McDonald Heather B, Winey Mark
Department of Molecular, Cellular, and Developmental Biology, University of Colorado-Boulder, Boulder, CO 80309, USA.
Mol Biol Cell. 2005 Aug;16(8):3606-19. doi: 10.1091/mbc.e04-10-0919. Epub 2005 Jun 8.
Centrins, small calcium binding EF-hand proteins, function in the duplication of a variety of microtubule organizing centers. These include centrioles in humans, basal bodies in green algae, and spindle pole bodies in yeast. The ciliate Tetrahymena thermophila contains at least four centrin genes as determined by sequence homology, and these have distinct localization and expression patterns. CEN1's role at the basal body was examined more closely. The Cen1 protein localizes primarily to two locations: one is the site at the base of the basal body where duplication is initiated. The other is the transition zone between the basal body and axoneme. CEN1 is an essential gene, the deletion of which results in the loss of basal bodies, which is likely due to defects in both basal body duplication and basal body maintenance. Analysis of the three other centrins indicates that two of them function at microtubule-rich structures unique to ciliates, whereas the fourth is not expressed under conditions examined in this study, although when artificially expressed it localizes to basal bodies. This study provides evidence that in addition to its previously known function in the duplication of basal bodies, centrin is also important for the integrity of these organelles.
中心蛋白是一类小型的钙结合EF手型蛋白，在多种微管组织中心的复制过程中发挥作用。这些微管组织中心包括人类的中心粒、绿藻的基体以及酵母的纺锤极体。通过序列同源性确定，纤毛虫嗜热栖热菌至少含有四个中心蛋白基因，并且这些基因具有不同的定位和表达模式。对CEN1在基体中的作用进行了更深入的研究。Cen1蛋白主要定位于两个位置：一个是基体基部开始复制的位点。另一个是基体与轴丝之间的过渡区。CEN1是一个必需基因，其缺失会导致基体丢失，这可能是由于基体复制和基体维持方面的缺陷所致。对其他三种中心蛋白的分析表明，其中两种在纤毛虫特有的富含微管的结构中发挥作用，而第四种在本研究检测的条件下不表达，不过人工表达时它会定位于基体。这项研究提供了证据，表明除了其先前已知的在基体复制中的功能外，中心蛋白对这些细胞器的完整性也很重要。
