Ouspenski I I, Elledge S J, Brinkley B R
Department of Cell Biology, Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA.
Nucleic Acids Res. 1999 Aug 1;27(15):3001-8. doi: 10.1093/nar/27.15.3001.
Phenotypes produced by gene overexpression may provide important clues to gene function. Here, we have performed a search for genes that affect chromo-some stability when overexpressed in the budding yeast Saccharomyces cerevisiae. We have obtained clones encompassing 30 different genes. Twenty-four of these genes have been previously characterized. Most of them are involved in chromatin dynamics, cell cycle control, DNA replication or mitotic chromosome segregation. Six novel genes obtained in this screen were named CST (chromosome stability). Based on the pattern of genomic instability, inter-action with checkpoint mutations and sensitivity to chromosome replication or segregation inhibitors, we conclude that overexpression of CST4 specifically interferes with mitotic chromosome segregation, and CST6 affects some aspect of DNA metabolism. The other CST genes had complex pleiotropic phenotypes. We have created deletions of five genes obtained in this screen, CST9, CST13, NAT1, SBA1 and FUN30. None of these genes is essential for viability, and deletions of NAT1 and SBA1 cause chromosome instability, a phenotype not previously associated with these genes. This work shows that analysis of dosage effects is complementary to mutational analysis of chromosome transmission fidelity, as it allows the identification of chromosome stability genes that have not been detected in mutational screens.
基因过表达产生的表型可能为基因功能提供重要线索。在此，我们对在芽殖酵母酿酒酵母中过表达时影响染色体稳定性的基因进行了搜索。我们获得了包含30个不同基因的克隆。其中24个基因先前已被鉴定。它们中的大多数参与染色质动态变化、细胞周期调控、DNA复制或有丝分裂染色体分离。在此筛选中获得的6个新基因被命名为CST（染色体稳定性）。基于基因组不稳定性模式、与检查点突变的相互作用以及对染色体复制或分离抑制剂的敏感性，我们得出结论，CST4的过表达特异性干扰有丝分裂染色体分离，而CST6影响DNA代谢的某些方面。其他CST基因具有复杂的多效性表型。我们对在此筛选中获得的5个基因CST9、CST13、NAT1、SBA1和FUN30进行了缺失构建。这些基因中没有一个对生存力是必需的，并且NAT1和SBA1的缺失导致染色体不稳定，这是一种以前未与这些基因相关联的表型。这项工作表明，剂量效应分析是对染色体传递保真度突变分析的补充，因为它允许鉴定在突变筛选中未检测到的染色体稳定性基因。
