Demeter J, Sazer S
Verna and Marrs McLean Department of Biochemistry, Baylor College of Medicine, Houston, Texas 77030, USA.
J Cell Biol. 1998 Oct 19;143(2):415-27. doi: 10.1083/jcb.143.2.415.
Cytokinesis is the part of the cell cycle in which the cell is cleaved to form two daughter cells. The unicellular yeast, Schizosaccharomyces pombe is an excellent model organism in which to study cell division, since it shows the general features of eukaryotic cell division and is amenable to genetic analysis. In this manuscript we describe the isolation and characterization of a new protein, imp2, which is required for normal septation in fission yeast. imp2, which colocalizes with the medial ring during septation, is structurally similar to a group of proteins including the S. pombe cdc15 and the mouse PSTPIP that are localized to, and thought to be involved in actin ring organization. Cells in which the imp2 gene is deleted or overexpressed have septation and cell separation defects. An analysis of the actin cytoskeleton shows the lack of a medial ring in septating cells that overexpress imp2, and the appearance of abnormal medial ring structures in septated cells that lack imp2. These observations suggest that imp2 destabilizes the medial ring during septation. imp2 also shows genetic interactions with several, previously characterized septation genes, strengthening the conclusion that it plays a role in normal fission yeast septation.
胞质分裂是细胞周期的一部分，在此过程中细胞被分裂形成两个子细胞。单细胞酵母粟酒裂殖酵母是研究细胞分裂的优秀模式生物，因为它展现了真核细胞分裂的一般特征且易于进行遗传分析。在本手稿中，我们描述了一种新蛋白质imp2的分离与特性，它是裂殖酵母正常隔膜形成所必需的。imp2在隔膜形成过程中与中间环共定位，在结构上与一组蛋白质相似，包括定位于肌动蛋白环并被认为参与肌动蛋白环组织的粟酒裂殖酵母cdc15和小鼠PSTPIP。imp2基因被缺失或过表达的细胞存在隔膜形成和细胞分离缺陷。对肌动蛋白细胞骨架的分析表明，过表达imp2的隔膜形成细胞中缺乏中间环，而缺乏imp2的隔膜形成细胞中出现异常的中间环结构。这些观察结果表明，imp2在隔膜形成过程中使中间环不稳定。imp2还与几个先前已表征的隔膜形成基因表现出遗传相互作用，强化了它在正常裂殖酵母隔膜形成中起作用的结论。
