Effects of null mutations and overexpression of capping protein on morphogenesis, actin distribution and polarized secretion in yeast.
Effects of null mutations and overexpression of capping protein on morphogenesis, actin distribution and polarized secretion in yeast.
复制标题
DOI：
10.1083/jcb.119.5.1151
复制
发表时间：
1992-12
期刊：
影响因子：
--
通讯作者：
Cooper JA
中科院分区：
文献类型：
--
作者：
Amatruda JF;Gattermeir DJ;Karpova TS;Cooper JA
CAP1是编码酿酒酵母加帽蛋白α亚基的基因，使用通过PCR制备的探针，用基于纯化的α亚基肽的氨基酸序列的引物克隆。该序列与其他物种的加帽蛋白α亚基序列相似，但与S.酿酒酵母加帽蛋白β亚基或任何其它蛋白质。通过分别或一起缺失CAP 1和CAP 2的编码区制备的加帽蛋白的突变体是可行的并且具有相似的表型。一个亚基的基因缺失导致另一个亚基的蛋白质缺失。无效突变体有一个严重的赤字肌动蛋白电缆和增加数量的肌动蛋白点在母亲。细胞呈圆形，相对较大。这些特征在细胞群体中是异质的，并且随遗传背景而变化。CAP1和CAP2的过表达还导致肌动蛋白索的丢失和细胞增大，以及异常形态发生和细胞壁增厚的额外特征。荧光标记的Con A表明，帽蛋白缺失菌株和过表达菌株在芽生长过程中表现出正常的极化分泌。突起形成和几丁质沉积响应交配信息素，交配效率，芽位选择也正常的加帽蛋白空菌株。此外，大量分泌的转化酶未受损。这些数据表明，肌动蛋白电缆是不需要的极化分泌在S。啤酒。
CAP1, the gene encoding the alpha subunit of Saccharomyces cerevisiae capping protein, was cloned using a probe prepared by PCR with primers based on the amino acid sequence of purified alpha subunit peptides. The sequence is similar to that of capping protein alpha subunits of other species but not to that of the S. cerevisiae capping protein beta subunit or any other protein. Null mutants of capping protein, prepared by deletion of the coding region of CAP1 and CAP2 separately or together, are viable and have a similar phenotype. Deletion of the gene for one subunit leads to a loss of protein for the other subunit. The null mutant has a severe deficit of actin cables and an increased number of actin spots in the mother. Cells are round and relatively large. These features are heterogeneous within a population of cells and vary with genetic background. Overexpression of CAP1 and CAP2 also causes loss of actin cables and cell enlargement, as well as the additional traits of aberrant morphogenesis and cell wall thickening. Capping protein null strains and overexpression strains exhibited normal polarized secretion during bud growth as demonstrated by labeling with fluoresceinated Con A. Projection formation and chitin deposition in response to mating pheromone, mating efficiency, and bud site selection were also normal in capping protein null strains. In addition, bulk secretion of invertase was unimpaired. These data indicate that actin cables are not required for polarized secretion in S. cerevisiae.