Fission yeast genes which disrupt mitotic chromosome segregation when overexpressed
Fission yeast genes which disrupt mitotic chromosome segregation when overexpressed
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DOI：
10.1093/nar/24.23.4676
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发表时间：
1996-12-01
影响因子：
14.9
通讯作者：
Allshire, RC
中科院分区：
文献类型：
--
作者：
Javerzat, JP;Cranston, G;Allshire, RC
在粟酒裂殖酵母中设计了干扰测定以快速鉴定和克隆涉及染色体分离的基因。在携带另外的非必需微型染色体的菌株中，从诱导型启动子过表达随机粟酒裂殖酵母cDNAs。过表达源自四个基因的cDNA，两个已知的（nda 3（+）和ubc 4（+），分别编码β-微管蛋白和泛素缀合酶）和两个未知的，名为mlo 2（+）和mlo 3（+）所有四种cDNA的完全过表达是致命的。过表达nda 3（+）和ubc 4（+）cDNA的细胞被浓缩的未分离染色体所阻滞，过表达mlo 2（+）的细胞显示出核染色质的不对称分布，nda 3（+）、ubc 4（+）和mlo 2（+）cDNA的亚致死水平的过表达导致了微小染色体丢失率的升高。第三种cDNA mlo 3（+）在亚致死水平的过表达下没有显示出微小染色体丢失频率的增加，但是完全过表达导致了染色体分离的完全失败，我们的研究结果证实了β-微管蛋白过表达在粟酒裂殖酵母中是致命的假设，暗示ubc 4（+）在控制分裂酵母的中期-后期转换中起作用，并最终鉴定出两个新基因，mlo 2（+）和mlo 3（+），可能在有丝分裂中染色体传递保真度中起重要作用。
An interference assay has been devised in Schizosaccharomyces pombe to rapidly identify and clone genes involved in chromosome segregation, Random S.pombe cDNAs were overexpressed from an inducible promoter in a strain carrying an additional, non-essential minichromosome, Overexpression of cDNAs derived from four genes, two known (nda3(+) and ubc4(+), encoding beta-tubulin and a ubiquitin conjugating enzyme, respectively) and two unknown, named mlo2(+) and mlo3(+) (missegregation & lethal when over expressed) caused phenotypes consistent with a failure to segregate chromosomes, Full overexpression of all four cDNAs was lethal, Cells overexpressing nda3(+) and ubc4(+) cDNAs arrested with condensed unsegregated chromosomes and cells overexpressing mlo2(+) displayed an asymmetric distribution of nuclear chromatin, Sublethal levels of overexpression of nda3(+), ubc4(+) and mlo2(+) cDNAs caused elevated rates of minichromosome loss, A third cDNA mlo3(+), displayed no increase in the frequency of minichromosome loss at sublethal levels of overexpression but full overexpression caused a complete failure to segregate chromosomes, Our results confirm the assumption that beta-tubulin overexpression is lethal in S.pombe, implicate ubc4(+) in the control of metaphase-anaphase transition in fission yeast and finally identify two new genes, mlo2(+) and mlo3(+), likely to play an important role for chromosome transmission fidelity in mitosis.