Karpova T S, Moltz S L, Riles L E, Güldener U, Hegemann J H, Veronneau S, Bussey H, Cooper J A
Department of Cell Biology and Physiology, Washington University, St Louis, MO 63110, USA.
J Cell Sci. 1998 Sep;111 ( Pt 17)(Pt 17):2689-96. doi: 10.1242/jcs.111.17.2689.
The yeast actin cytoskeleton is polarized during most of the cell cycle. Certain environmental factors and mutations are associated with depolarization of the actin cytoskeleton. Is depolarization of the actin cytoskeleton a specific response, or is it a nonspecific reaction to harsh conditions or poor metabolism? If depolarization is a nonspecific response, then any mutation that slows growth should induce depolarization. In addition, the number of genes with the depolarization phenotype should constitute a relatively large part of the genome. To address this question, we determined the effect of slow growth on the actin cytoskeleton, and we determined the frequency of mutations that affect the actin cytoskeleton. Eight mutants with slow growth showed no defect in actin polarization, indicating that slow growth alone is not sufficient to cause depolarization. Among 273 viable haploids disrupted for ORFs of chromosome I and VIII and 950 viable haploids with random genome disruptions, none had depolarization of the cytoskeleton. We conclude that depolarization of the actin cytoskeleton is a specific phenotype.
酵母肌动蛋白细胞骨架在细胞周期的大部分时间里是极化的。某些环境因素和突变与肌动蛋白细胞骨架的去极化有关。肌动蛋白细胞骨架的去极化是一种特异性反应，还是对恶劣条件或代谢不良的非特异性反应？如果去极化是非特异性反应，那么任何减缓生长的突变都应该诱导去极化。此外，具有去极化表型的基因数量应该在基因组中占相当大的比例。为了解决这个问题，我们确定了生长缓慢对肌动蛋白细胞骨架的影响，并确定了影响肌动蛋白细胞骨架的突变频率。八个生长缓慢的突变体在肌动蛋白极化方面没有缺陷，这表明仅生长缓慢不足以导致去极化。在273个破坏了I号和VIII号染色体开放阅读框的可存活单倍体以及950个基因组随机破坏的可存活单倍体中，没有一个细胞骨架发生去极化。我们得出结论，肌动蛋白细胞骨架的去极化是一种特异性表型。
