A TEMPERATURE-SENSITIVE MUTATION AFFECTING SYNTHESIS OF OUTER ARM DYNEINS IN TETRAHYMENA-THERMOPHILA
A TEMPERATURE-SENSITIVE MUTATION AFFECTING SYNTHESIS OF OUTER ARM DYNEINS IN TETRAHYMENA-THERMOPHILA
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DOI：
10.1111/j.1550-7408.1992.tb01312.x
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发表时间：
1992-03-01
期刊：
影响因子：
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通讯作者：
PENNOCK, DG
中科院分区：
文献类型：
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作者：
ATTWELL, GJ;BRICKER, CS;PENNOCK, DG
我们的特点是一个新的，温度敏感的突变影响运动在四膜虫嗜热。突变体在限制性温度（38 ℃）下正常生长和分裂，但变得不动。扫描电子显微镜分析表明，不动的突变体含有正常数量的纤毛和纤毛的正常长度。透射电镜分析表明，从非运动突变体分离的轴丝缺乏外动力蛋白臂，因此该突变被命名为oad 1（外臂缺陷）。在阻止细胞生长和分裂（饥饿）的条件下，移动到38 ℃的运动突变体仍然保持运动，这表明一旦在允许的温度（28 ℃）下组装成轴丝，外臂动力蛋白在38 ℃下仍然具有功能。饥饿，deciliated突变体再生的功能纤毛在38度C的一个完整的补充，表明该机制，将外臂动力蛋白到发展中的轴丝不受oad 1突变。饥饿，nonmotile突变体恢复运动时，转移回28摄氏度，但不是孵育时与放线菌酮。我们解释这些结果排除了oad 1突变影响微管外臂动力蛋白结合位点的假设。从在38 ℃下生长一代的突变体中分离的轴丝平均具有6.0个外臂动力蛋白，从在38 ℃下生长两代的突变体中分离的轴丝平均具有3.2个外臂动力蛋白。综上所述，这些结果表明oad 1突变影响四膜虫外臂动力蛋白的合成。
We have characterized a novel, temperature-sensitive mutation affecting motility in Tetrahymena thermophila. Mutants grew and divided normally at the restrictive temperature (38-degrees-C), but became nonmotile. Scanning electron microscopic analysis indicated that nonmotile mutants contained the normal number of cilia and that the cilia were of normal length. Transmission electron microscopic analysis indicated that axonemes isolated from nonmotile mutants lacked outer dynein arms, so the mutation was named oad 1 (outer arm deficient). Motile mutants shifted to 38-degrees-C under conditions that prevent cell growth and division (starvation) remained motile suggesting that once assembled into axonemes at the permissive temperature (28-degrees-C) the outer arm dyneins remain functional at 38-degrees-C. Starved, deciliated mutants regenerated a full complement of functional cilia at 38-degrees-C, indicating that the mechanism that incorporates the outer arm dynein into developing axonemes is not affected by the oad 1 mutation. Starved, nonmotile mutants regained motility when shifted back to 28-degrees-C, but not when incubated with cycloheximide. We interpret these results to rule out the hypothesis that the oad 1 mutation affects the site on the microtubules to which the outer arm dyneins bind. Axonemes isolated from mutants grown for one generation at 38-degrees-C had a mean of 6.0 outer arm dyneins, and axonemes isolated from mutants grown for two generations at 38-degrees-C had a mean of 3.2 outer arm dyneins. Taken together, these results indicate that the oad 1 mutation affects the synthesis of outer arm dyneins in Tetrahymena.