Components of a "dynein regulatory complex" are located at the junction between the radial spokes and the dynein arms in Chlamydomonas flagella.
Components of a "dynein regulatory complex" are located at the junction between the radial spokes and the dynein arms in Chlamydomonas flagella.
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DOI：
10.1083/jcb.127.5.1311
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发表时间：
1994-12
影响因子：
7.8
通讯作者：
Porter, M E
中科院分区：
文献类型：
--
作者：
Gardner, L C;O'Toole, E;Perrone, C A;Giddings, T;Porter, M E
先前对鞭毛突变体的研究已经确定了六种轴突多肽作为“动力蛋白调节复合体”（DRC）的组成部分。DRC被认为是协调多个鞭毛动力蛋白的活动，但其在轴突内的位置尚不清楚（Huang et al., 1982; Piperno et al., 1992）。我们使用改进的色谱方法（Kagami和Kamiya， 1992）和EM图像的计算机平均（Mastronarde等人，1992）来分析DRC和动力臂之间的关系。我们的结果表明，一些DRC组件位于第二个径向辐条的底部，与内动力臂密切相关。(a)轴素截面的平均值表明，三个DRC突变体（pf3 < pf2 < sup-pf-3 < wt）的内臂结构显著减少。(b)这些缺陷在轴突远端/内侧区域比近端区域更为明显。(c)通过快速蛋白液相色谱和SDS-PAGE对鞭毛提取物的分析表明，pf3中缺少一个特定的动力蛋白I2异构体，pf2和supp -pf-3中减少。与ida4和pf3ida4提取物的比较表明，该异构体与ida4中缺失的异构体不同。(d)纵切面观察，所有三个DRC突变体在第二个径向辐条以上都缺乏月牙形密度，pf3轴突体在月牙形附近缺乏额外的结构。我们认为新月部分对应于DRC的位置，并且这种结构也与内动力臂的一个子集直接相关。这个位置是合适的复合体，被认为是调解信号之间的径向辐条和动力臂。
Previous studies of flagellar mutants have identified six axonemal polypeptides as components of a "dynein regulatory complex" (DRC). The DRC is though to coordinate the activity of the multiple flagellar dyneins, but its location within the axoneme has been unknown (Huang et al., 1982; Piperno et al., 1992). We have used improved chromatographic procedures (Kagami and Kamiya, 1992) and computer averaging of EM images (Mastronarde et al., 1992) to analyze the relationship between the DRC and the dynein arms. Our results suggest that some of the DRC components are located at the base of the second radial spoke in close association with the inner dynein arms. (a) Averages of axoneme cross- sections indicate that inner arm structures are significantly reduced in three DRC mutants (pf3 < pf2 < sup-pf-3 < wt). (b) These defects are more pronounced in distal/medial regions of the axoneme than in proximal regions. (c) Analysis of flagellar extracts by fast protein liquid chromatography and SDS-PAGE indicates that a specific dynein I2 isoform is missing in pf3 and reduced in pf2 and sup-pf-3. Comparison with ida4 and pf3ida4 extracts reveals that this isoform differs from those missing in ida4. (d) When viewed in longitudinal section, all three DRC mutants lack a crescent-shaped density above the second radial spoke, and pf3 axonemes lack additional structures adjacent to the crescent. We propose that the crescent corresponds in part to the location of the DRC, and that this structure is also directly associated with a subset of the inner dynein arms. This position is appropriate for a complex that is thought to mediate signals between the radial spokes and the dynein arms.