The sup-pf-2 mutations of Chlamydomonas alter the activity of the outer dynein arms by modification of the gamma-dynein heavy chain
The sup-pf-2 mutations of Chlamydomonas alter the activity of the outer dynein arms by modification of the gamma-dynein heavy chain
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DOI：
10.1083/jcb.135.6.1853
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发表时间：
1996-12-01
影响因子：
7.8
通讯作者：
Porter, ME
中科院分区：
文献类型：
--
作者：
Rupp, G;OToole, E;Porter, ME
Sup-pF-2突变是一组动力蛋白调节突变的成员，这些突变能够恢复瘫痪的中心对或放射状缺陷菌株的运动能力。以前的工作表明，在sup-pF-2中鞭毛节拍频率降低，但对sup-pF-a表型知之甚少(Huang，B.，Z.Ramanis，和D.J.L.Lucy，1982)。牢房。28：115-125；Brokaw，C.J.，和D.J.L.，Luck。1985年，细胞运动。5：195-208)，我们利用改进的生化和结构技术以及对额外的sup-pF-2等位基因的分析，重新检测了sup-pF-2。我们已经发现，sup-pF-2突变与外动力素臂的缺陷有关。对sup-pF-2-1轴丝的生化分析表明，与野生型相比，轴丝ATPase活性和外臂多肽都降低了40-50%。通过薄层扫描，这些缺陷与不同于45%的外动力蛋白臂结构的损失有关。有趣的是，这种损失偏向于外部双重体的子集，导致径向不对称，这可能反映了外臂组装的某些方面。外臂组装的缺陷似乎不是由外双线微管或外臂对接结构的缺陷引起的，而是由外臂动力蛋白组件的缺陷引起的。对新的sup-PF-2突变的分析表明，外臂组装缺陷的严重程度因等位基因而异。互补试验和连锁分析表明，sup-pF-2突变是PF28/ODA2基因座的等位基因，该基因座被认为编码外臂的Gamma-dynein重链亚单位。因此，sup-pF-2突变似乎通过改变伽马动力蛋白重链来改变外部动力蛋白手臂的活性。
The sup-pf-2 mutation is a member of a group of dynein regulatory mutations that are capable of restoring motility to paralyzed central pair or radial spoke defective strains. Previous work has shown that the flagellar beat frequency is reduced in sup-pf-2, but little else was known about the sup-pf-a phenotype (Huang, B., Z. Ramanis, and D.J.L. Luck, 1982. Cell. 28:115-125; Brokaw, C.J., and D.J.L, Luck. 1985, Cell Motil. 5:195-208), We have reexamined sup-pf-2 using improved biochemical and structural techniques and by the analysis of additional sup-pf-2 alleles. We have found that the sup-pf-2 mutations are associated with defects in the outer dynein arms. Biochemical analysis of sup-pf-2-1 axonemes indicates that both axonemal ATPase activity and outer arm polypeptides are reduced by 40-50% when compared with wild type. By thin-section EM, these defects correlate with an not similar to 45% loss of outer dynein arm structures. Interestingly, this loss is biased toward a subset of outer doublets, resulting in a radial asymmetry that may reflect some aspect of outer arm assembly. The defects in outer arm assembly do not appear to result from defects in either the outer doublet microtubules or the outer arm docking structures, but rather appear to result from defects in outer dynein arm components, Analysis of new sup-pf-2 mutations indicates that the severity of the outer arm assembly defects varies with different alleles. Complementation tests and linkage analysis reveal that the sup-pf-2 mutations are alleles of the PF28/ODA2 locus, which is thought to encode the gamma-dynein heavy chain subunit of the outer arm. The sup-pf-2 mutations therefore appear to alter the activity of the outer dynein arms by modification of the gamma-dynein heavy chain.