Distinct mutants of retrograde intraflagellar transport (IFT) share similar morphological and molecular defects.
Distinct mutants of retrograde intraflagellar transport (IFT) share similar morphological and molecular defects.
复制标题
DOI：
10.1083/jcb.143.6.1591
复制
发表时间：
1998-12-14
影响因子：
7.8
通讯作者：
Sassaroli, M
中科院分区：
文献类型：
--
作者：
Piperno, G;Siuda, E;Henderson, S;Segil, M;Vaananen, H;Sassaroli, M
基于微管的蛋白质复合物运输是双向的，发生在衣藻鞭毛的基体周围空间和远端部分之间，被称为鞭毛内运输（IFT）。 IFT 涉及分子马达和由 17S 蛋白质复合物组成的颗粒。为了确定 IFT 机制不同组件的功能，我们分离并表征了代表基因座 FLA15、FLA16 和 FLA17 的鞭毛组装的四种温度敏感 (ts) 突变体。这些突变体在鞭毛组装的其他 ts 突变体中被选择，因为它们表现出鞭毛膜的特征性凸起作为非条件表型。这些突变体中的每一个都在粒子的逆行速度和双向传输的频率方面存在显着缺陷，但在粒子的顺行速度方面没有显着缺陷，正如一种新的 IFT 分析方法所揭示的，该方法允许跟踪视频图像序列中的单个粒子。此外，每个突变体都存在 17S 复合物的相同四个亚基缺陷，该复合物早先被鉴定为 IFT 复合物 A。作为三个基因座中任何一个突变的结果，同一组表型的出现表明了这样的假设：复合物 A 是专门参与逆行鞭毛内运动的 IFT 颗粒的一部分。
A microtubule-based transport of protein complexes, which is bidirectional and occurs between the space surrounding the basal bodies and the distal part of Chlamydomonas flagella, is referred to as intraflagellar transport (IFT). The IFT involves molecular motors and particles that consist of 17S protein complexes. To identify the function of different components of the IFT machinery, we isolated and characterized four temperature-sensitive (ts) mutants of flagellar assembly that represent the loci FLA15, FLA16, and FLA17. These mutants were selected among other ts mutants of flagellar assembly because they displayed a characteristic bulge of the flagellar membrane as a nonconditional phenotype. Each of these mutants was significantly defective for the retrograde velocity of particles and the frequency of bidirectional transport but not for the anterograde velocity of particles, as revealed by a novel method of analysis of IFT that allows tracking of single particles in a sequence of video images. Furthermore, each mutant was defective for the same four subunits of a 17S complex that was identified earlier as the IFT complex A. The occurrence of the same set of phenotypes, as the result of a mutation in any one of three loci, suggests the hypothesis that complex A is a portion of the IFT particles specifically involved in retrograde intraflagellar movement.