Flescher E G, Madden K, Snyder M
Department of Biology, Yale University, New Haven, Connecticut 06511.
J Cell Biol. 1993 Jul;122(2):373-86. doi: 10.1083/jcb.122.2.373.
Polarized cell division is a fundamental process that occurs in a variety of organisms; it is responsible for the proper positioning of daughter cells and the correct segregation of cytoplasmic components. The SPA2 gene of yeast encodes a nonessential protein that localizes to sites of cell growth and to the site of cytokinesis. spa2 mutants exhibit slightly altered budding patterns. In this report, a genetic screen was used to isolate a novel ochre allele of CDC10, cdc10-10; strains containing this mutation require the SPA2 gene for growth. CDC10 encodes a conserved potential GTP-binding protein that previously has been shown to localize to the bud neck and to be important for cytokinesis. The genetic interaction of cdc10-10 and spa2 suggests a role for SPA2 in cytokinesis. Most importantly, strains that contain a cdc10-10 mutation and those containing mutations affecting other putative neck filament proteins do not form buds at their normal proximal location. The finding that a component involved in cytokinesis is also important in bud site selection provides strong evidence for the cytokinesis tag model; i.e., critical components at the site of cytokinesis are involved in determining the next site of polarized growth and division.
极化细胞分裂是一个在多种生物体中发生的基本过程；它负责子细胞的正确定位以及细胞质成分的正确分离。酵母的SPA2基因编码一种非必需蛋白，该蛋白定位于细胞生长位点和胞质分裂位点。spa2突变体表现出略有改变的出芽模式。在本报告中，通过遗传筛选分离出了CDC10的一个新的赭石型等位基因cdc10-10；含有这种突变的菌株生长需要SPA2基因。CDC10编码一种保守的潜在GTP结合蛋白，此前已证明该蛋白定位于芽颈，对胞质分裂很重要。cdc10-10与spa2的遗传相互作用表明SPA2在胞质分裂中起作用。最重要的是，含有cdc10-10突变的菌株以及含有影响其他假定颈部丝状蛋白突变的菌株不会在其正常的近端位置形成芽。胞质分裂相关成分在芽位点选择中也很重要这一发现为胞质分裂标签模型提供了有力证据；即，胞质分裂位点的关键成分参与确定极化生长和分裂的下一个位点。
