Studies concerning the temporal and genetic control of cell polarity in Saccharomyces cerevisiae.
Studies concerning the temporal and genetic control of cell polarity in Saccharomyces cerevisiae.
复制标题
关于酿酒酵母中细胞极性的时间和遗传控制的研究。
DOI：
10.1083/jcb.114.3.515
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发表时间：
1991-08
影响因子：
7.8
通讯作者：
Page, B D
中科院分区：
文献类型：
--
作者：
Snyder, M;Gehrung, S;Page, B D
在芽殖酵母酿酒酵母中检查了细胞极性的建立。使用同步细胞和 cdc 突变体在整个酵母细胞周期中跟踪极化蛋白 SPA2 蛋白的分布。 SPA2 蛋白定位于 G1 细胞假定芽位点的一个斑块上。随后它集中在芽尖的芽细胞中。在胞质分裂时，SPA2 蛋白位于母细胞和子细胞之间的颈部。对未出芽单倍体细胞的分析表明在 G1 期间发生了一系列事件。 SPA2 补片在 G1 很早就建立，而纺锤体极体残留在核的远端。随后，从纺锤体极体发出的微管与 SPA2 新月体相交，细胞核可能向 SPA2 斑块旋转。到 G1 中期，大多数细胞在靠近 SPA2 斑块的细胞核一侧含有 SPB，并且长的核外微管束与该斑块相交。我们认为 SPA2 染色区域存在微管捕获位点，可以稳定长微管束；该捕获位点可能负责细胞核的旋转。含有 SPA2 蛋白极化分布的细胞在同一区域也具有极化分布的肌动蛋白斑点，尽管肌动蛋白染色更加分散。此外，在限制温度下形成多个芽的cdc4突变体在芽尖的子集中表现出SPA2蛋白和肌动蛋白斑点的同时染色。 spa2 突变体含有极化分布的肌动蛋白点，而 act1-1 和 act1-2 突变体通常含有极化分布的 SPA2 蛋白，表明 SPA2 蛋白不是肌动蛋白点定位所必需的，并且 SPA2 蛋白定位也不需要肌动蛋白点。 cdc24突变体在限制温度下无法形成芽，无法表现出SPA2蛋白和肌动蛋白斑点的极化定位，表明CDC24蛋白直接或间接负责控制这些蛋白的极性。基于SPA2蛋白的细胞周期分布，提出了“细胞分裂标签”模型来解释单倍体酵母细胞中芽位点非随机定位的机制。
The establishment of cell polarity was examined in the budding yeast, S. cerevisiae. The distribution of a polarized protein, the SPA2 protein, was followed throughout the yeast cell cycle using synchronized cells and cdc mutants. The SPA2 protein localizes to a patch at the presumptive bud site of G1 cells. Later it concentrates at the bud tip in budded cells. At cytokinesis, the SPA2 protein is at the neck between the mother and daughter cells. Analysis of unbudded haploid cells has suggested a series of events that occurs during G1. The SPA2 patch is established very early in G1, while the spindle pole body residues on the distal side of the nucleus. Later, microtubules emanating from the spindle pole body intersect the SPA2 crescent, and the nucleus probably rotates towards the SPA2 patch. By middle G1, most cells contain the SPB on the side of the nucleus proximal to the SPA2 patch, and a long extranuclear microtubule bundle intersects this patch. We suggest that a microtubule capture site exists in the SPA2 staining region that stabilizes the long microtubule bundle; this capture site may be responsible for rotation of the nucleus. Cells containing a polarized distribution of the SPA2 protein also possess a polarized distribution of actin spots in the same region, although the actin staining is much more diffuse. Moreover, cdc4 mutants, which form multiple buds at the restrictive temperature, exhibit simultaneous staining of the SPA2 protein and actin spots in a subset of the bud tips. spa2 mutants contain a polarized distribution of actin spots, and act1-1 and act1-2 mutants often contain a polarized distribution of the SPA2 protein suggesting that the SPA2 protein is not required for localization of the actin spots and the actin spots are not required for localization of the SPA2 protein. cdc24 mutants, which fail to form buds at the restrictive temperature, fail to exhibit polarized localization of the SPA2 protein and actin spots, indicating that the CDC24 protein is directly or indirectly responsible for controlling the polarity of these proteins. Based on the cell cycle distribution of the SPA2 protein, a "cytokinesis tag" model is proposed to explain the mechanism of the non-random positioning of bud sites in haploid yeast cells.