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Regulation of chromosome segregation in the budding yeast, S.cerevisiae

芽殖酵母酿酒酵母染色体分离的调控

基本信息

批准号：
11660093
负责人：
TSUCHIYA Eiko
金额：
$ 2.43万
依托单位：
Hiroshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

NPS1/STH1 encodes a catalytic subunit of RSC and plays essential role for mitotic growth. Our previous analysis on temperature-sensitive mutant allele of NPS1, nps1-105, revealed that Nps1/RSC plays important role on the assembly and/or maintenance of the chromatin structure around centromeres. We performed this study on an attempt to understand the in vivo function of RSC and obtained the following results.1) We isolated fifteen suppressor mutants (rtn mutants) that can restore the growth of nps1-105 in the presence of TBZ.These mutants were classified in nine complementation groups. Taking an advantage of temperature sensitivity, we cloned RTN2, RTN4 and RTN5 and identified them as NUP82, ABD1 and CET1, respectively.2) We screened high-copy suppressor genes for the temperature- and thiabendazole (TBZ) nps1-105 mutant and identified nine genes including NPS1. Among those, PKC1 and BIM1 that respectively encoded a homolog of mammalian protein kinase C and a conserved microtubule binding protein homologous to human EB1 were found to play important role on suppression. Genetic analysis of the functional relationships between these genes revealed that PKC1 suppressed the defect of nps1-105 via the function of BIM1 but not through activation of the MPK1/MAPK pathway. The stt1 mutation showed TBZ sensitivity and delayed G2-phase progression at semi-permissive temperatures. Both of these stt1 phenotypes were suppressed by the overexpression of BIM1. In addition, stt1 as well as nps1-105, mis-segregated a mini-chromosome at higher frequency than the wild type at permissive temperature. The mis-segregation was enhanced in the nps1-105 stt1 double mutant. These results suggested that Pkc1p plays a role relevant to microtubule function and that this role is mediated by an unknown PKC effector branch and by Bim1p.

NPS 1/STH 1编码RSC的催化亚基，在有丝分裂生长中起重要作用。我们先前对NPS 1温度敏感突变等位基因nps 1 -105的分析表明，Nps 1/RSC在着丝粒周围染色质结构的组装和/或维持中起重要作用。本研究旨在了解RSC在体内的功能，并获得以下结果：1）我们分离了15个抑制突变体（rtn突变体），这些突变体可以在TBZ存在下恢复nps 1 -105的生长，这些突变体被分为9个互补组。利用温度敏感性，克隆了RTN 2、RTN 4和RTN 5，分别鉴定为NUP 82、ABD 1和CET 1。2）筛选了温度和噻菌灵（TBZ）nps 1 -105突变体的高拷贝抑制基因，鉴定了包括NPS 1在内的9个基因。其中，PKC 1和BIM 1分别编码哺乳动物蛋白激酶C的同源物和与人EB 1同源的保守微管结合蛋白，被发现在抑制中起重要作用。这些基因之间的功能关系的遗传分析表明，PKC 1抑制nps 1 -105的缺陷，通过BIM 1的功能，而不是通过激活MPK 1/MAPK通路。stt 1突变显示TBZ敏感性和延迟G2期进展在半容许温度。这两种stt 1表型都被BIM 1的过表达所抑制。此外，stt 1和nps 1 -105在允许温度下以比野生型更高的频率错误分离一条小染色体。在nps 1 -105 stt 1双突变体中，错分离增强。这些结果表明，PKC 1 p发挥作用相关的微管功能，这一作用是由一个未知的PKC效应分支和Bim 1 p介导的。