Tucker J B, Mogensen M M, Henderson C G, Doxsey S J, Wright M, Stearns T
School of Biomedical Sciences, University of St Andrews, Scotland, UK.
J Anat. 1998 Jan;192 ( Pt 1)(Pt 1):119-30. doi: 10.1046/j.1469-7580.1998.19210119.x.
This report deals with the as yet undetermined issue of whether cell-surface associated microtubules in certain cochlear epithelial cells are centrosomally nucleated and subsequently migrate to microtubule-capturing sites located at the surface regions in question. Alternatively, the cells may possess additional nucleating sites which are noncentrosomal and surface-associated. These alternative possibilities have been investigated for highly polarised epithelial cells called supporting cells in the mouse and guinea pig organ of Corti using antibodies to pericentrin and gamma-tubulin. There is substantial evidence that both proteins are essential components of microtubule-nucleating sites in cells generally. Each mature supporting cell possesses a large microtubule array that is remotely located with respect to its centrosome (more than 10 microns away). The antibodies bind to a cell's centrosome. No binding has been detected at 2 other microtubule-organising centres that are associated with the ends of the centrosomally-remote microtubule array while it is being constructed. Such arrays include thousands of microtubules in some of the cell types that have been examined. If all a cell's microtubules are nucleated by its centrosome then the findings reported above imply that microtubules escape from the centrosomal nucleating site and migrate to a new location. Furthermore capture of the plus and minus ends of the errant microtubules is taking place because both ends of a centrosomally-remote microtubule array are attached to sites that are precisely positioned at certain cell surface locations. Minus ends are locating targets with an exactitude comparable to that which has been demonstrated for plus ends in certain cell types. These cells apparently operate a single control centre strategy for microtubule nucleation that is complemented by precise positioning of plus and minus end-capturing sites at the cell surface.
本报告探讨了一个尚未确定的问题，即某些耳蜗上皮细胞中与细胞表面相关的微管是否由中心体成核，随后迁移到位于上述表面区域的微管捕获位点。或者，这些细胞可能具有额外的非中心体且与表面相关的成核位点。利用针对中心粒外周蛋白和γ-微管蛋白的抗体，对小鼠和豚鼠柯蒂氏器中称为支持细胞的高度极化上皮细胞的这些替代可能性进行了研究。有大量证据表明，这两种蛋白质通常是细胞中微管成核位点的重要组成部分。每个成熟的支持细胞都拥有一个相对于其中心体位置较远（超过10微米）的大型微管阵列。这些抗体与细胞的中心体结合。在构建与中心体远端微管阵列末端相关的另外两个微管组织中心时，未检测到结合。在一些已检测的细胞类型中，这样的阵列包含数千根微管。如果一个细胞的所有微管都由其中心体成核，那么上述研究结果意味着微管从中心体成核位点逸出并迁移到新的位置。此外，正在发生对错误微管正负两端的捕获，因为中心体远端微管阵列的两端都附着在精确位于某些细胞表面位置的位点上。负端定位目标的精确程度与某些细胞类型中已证明的正端相当。这些细胞显然采用单一控制中心策略进行微管成核，并辅以细胞表面正负端捕获位点的精确定位。
