Maeda Yukari, Kashiwazaki Jun, Shimoda Chikashi, Nakamura Taro
Department of Biology, Graduate School of Science, Osaka City University, Japan.
Biosci Biotechnol Biochem. 2009 Feb;73(2):339-45. doi: 10.1271/bbb.80575. Epub 2009 Feb 7.
Syntaxin is a component of t-soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE), which is responsible for docking membrane vesicles at the target membrane and is highly conserved among eukaryotes. In the fission yeast Schizosaccharomyces pombe, the psy1(+) gene encoding a syntaxin 1 homolog was originally isolated as a multicopy suppressor of the sporulation-deficient mutant, spo3, but little is known about the way Psy1 is involved in sporulation. Here we report the isolation of a sporulation-defective mutant, psy1-S1, generated by random PCR mutagenesis. psy1-S1 also exhibited temperature sensitivity in growth. In psy1-S1 cells, assembly of the forespore membrane (FSM) initiated near the spindle pole bodies during meiosis II, but subsequent expansion of the membrane was severely impaired. Overproduction of the cognate SNARE proteins, Syb1 and Sec9, suppressed both the temperature sensitivity and sporulation defects of psy1-S1. These results indicate that Psy1 plays an essential role in FSM formation coordinated by Syb1 and Sec9.
Syntaxin是可溶性N - 乙基马来酰亚胺敏感因子附着蛋白受体（SNARE）的一个组成部分，负责将膜泡对接至靶膜，并且在真核生物中高度保守。在裂殖酵母粟酒裂殖酵母中，编码Syntaxin 1同源物的psy1(+)基因最初是作为孢子形成缺陷突变体spo3的多拷贝抑制子被分离出来的，但关于Psy1参与孢子形成的方式知之甚少。在此我们报告通过随机PCR诱变产生的一个孢子形成缺陷突变体psy1-S1的分离情况。psy1-S1在生长方面也表现出温度敏感性。在psy1-S1细胞中，前孢子膜（FSM）的组装在减数分裂II期间于纺锤体极体附近起始，但随后膜的扩展严重受损。同源SNARE蛋白Syb1和Sec9的过量表达抑制了psy1-S1的温度敏感性和孢子形成缺陷。这些结果表明，Psy1在由Syb1和Sec9协调的FSM形成中起重要作用。
