THE COLR4 AND COLR15 BETA-TUBULIN MUTATIONS IN CHLAMYDOMONAS-REINHARDTII CONFER ALTERED SENSITIVITIES TO MICROTUBULE INHIBITORS AND HERBICIDES BY ENHANCING MICROTUBULE STABILITY
THE COLR4 AND COLR15 BETA-TUBULIN MUTATIONS IN CHLAMYDOMONAS-REINHARDTII CONFER ALTERED SENSITIVITIES TO MICROTUBULE INHIBITORS AND HERBICIDES BY ENHANCING MICROTUBULE STABILITY
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DOI：
10.1083/jcb.113.3.605
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发表时间：
1991-05-01
影响因子：
7.8
通讯作者：
HUANG, B
中科院分区：
文献类型：
--
作者：
SCHIBLER, MJ;HUANG, B
莱茵衣藻中赖氨酸-350的col（R）4和col（R）15 β-2-微管蛋白错义突变（Lee和Huang，1990）最初是通过选择对秋水仙素生长抑制作用的抗性而分离的。已发现col（R）4和col（R）15突变体对长春碱和几类抗有丝分裂除草剂具有交叉抗性，所述抗有丝分裂除草剂包括二硝基苯胺（安磺灵、氟乐灵、氟乐灵和乙氟乐灵）;磷酰胺甲基丙氨磷;和二甲基丙炔苯甲酰胺丙酰胺。与秋水仙碱和长春碱一样，这些植物特异性除草剂的抗有丝分裂作用与微管的解聚有关。与它们对微管解聚药物的抗性相反，突变体对紫杉醇的敏感性增加，紫杉醇是一种增强微管聚合和稳定性的药物。发现这种对不同微管抑制剂的敏感性改变的模式与β-微管蛋白突变共分离和共回复，这提供了第一个遗传证据，即二硝基苯胺类、甲基氨丙磷和丙虫酰胺的体内除草作用与微管功能有关。尽管在生长特性上与野生型相似，但发现col（R）4和col（R）15突变体具有改变的微管模式，所述微管包含乙酰化α-微管蛋白，这是一种翻译后修饰，其与在多种细胞中发现的稳定的微管亚群相关。微管在间期细胞质和有丝分裂细胞的核内纺锤体，在野生型衣原体细胞中不包含乙酰化的α-微管蛋白，被发现在突变体中乙酰化。这些数据一起表明，col（R）4和col（R）15错义突变增加了掺入突变体β-微管蛋白的微管的稳定性，并且突变体的药物敏感性改变是这种增强的微管稳定性的结果。
The col(R)4 and col(R)15 beta-2-tubulin missense mutations for lysine-350 in Chlamydomonas reinhardtii (Lee and Huang, 1990) were originally isolated by selection for resistance to the growth inhibitory effects of colchicine. The col(R)4 and col(R)15 mutants have been found to be cross resistant to vinblastine and several classes of antimitotic herbicides, including the dinitroanilines (oryzalin, trifluralin, profluralin, and ethafluralin); the phosphoric amide amiprophos methyl; and the dimethyl propynl benzamide pronamide. Like colchicine and vinblastine, the antimitotic effects of these plant-specific herbicides have been associated with the depolymerization of microtubules. In contrast to their resistance to microtubule-depolymerizing drugs, the mutants have an increased sensitivity to taxol, a drug which enhances the polymerization and stability of microtubules. This pattern of altered sensitivity to different microtubule inhibitors was found to cosegregate and corevert with the beta-tubulin mutations providing the first genetic evidence that the in vivo herbicidal effects of the dinitroanilines, amiprophos methyl, and pronamide are related to microtubule function. Although wild-type like in their growth characteristics, the col(R)4 and col(R)15 mutants were found to have an altered pattern of microtubules containing acetylated alpha-tubulin, a posttranslational modification that has been associated with stable subsets of microtubules found in a variety of cells. Microtubules in the interphase cytoplasm and those of the intranuclear spindle of mitotic cells, which in wild-type Chlamydomonas cells do not contain acetylated alpha-tubulin, were found to be acetylated in the mutants. These data taken together suggest that the col(R)4 and col(R)15 missense mutations increase the stability of the microtubules into which the mutant beta-tubulins are incorporated and that the altered drug sensitivities of the mutants are a consequence of this enhanced microtubule stabilitty.