snf/swi mutants of S. cerevisiae.. Saccharomyces cerevisiae

The Saccharomyces cerevisiae Snf/Swi complex has been previously demonstrated to control transcription and chromatin structure of particular genes in vivo and to remodel nucleosomes in vitro. We have performed whole-genome expression analysis, using DNA microarrays, to study mutants deleted for a gene encoding one conserved (Snf2) or one unconserved (Swi1) Snf/Swi component. This analysis was performed on cells grown in both rich and minimal media. The microarray results, combined with Northern blot, computational, and genetic analyses, show that snf2Delta and swi1Delta mutations cause similar effects on mRNA levels, that Snf/Swi controls some genes differently in rich and minimal media, and that Snf/Swi control is exerted at the level of individual genes rather than over larger chromosomal domains. In addition, this work shows that Snf/Swi controls mRNA levels of MATalpha-specific genes, likely via controlling transcription of the regulators MATalpha1 and MCM1. Finally, we provide evidence that Snf/Swi acts both as an activator and as a repressor of transcription, and that neither mode of control is an indirect effect of the other. This study is described in more detail in Sudarsanam P et al.(2000) Proc Natl Acad Sci U S A 97:3364-9 Keywords: other酿酒酵母（Saccharomyces cerevisiae）的Snf/Swi复合物此前已被证实可在体内调控特定基因的转录与染色质结构，并能在体外重塑核小体。我们利用DNA微阵列（DNA microarray）开展全基因组表达分析，针对编码Snf/Swi复合物保守组分Snf2与非保守组分Swi1的基因敲除突变体进行研究。该分析分别在富营养培养基与基本培养基中培养的细胞上完成。结合Northern印迹（Northern blot）、生物信息学分析与遗传学实验的微阵列结果显示：snf2Δ与swi1Δ突变对mRNA水平的影响相似；Snf/Swi复合物在富营养与基本培养基中对部分基因的调控模式存在差异；且Snf/Swi的调控作用靶向单个基因，而非更大范围的染色体结构域。此外，本研究证实Snf/Swi复合物可调控MATα特异性基因的mRNA水平，其机制可能通过调控调控因子MATα1与MCM1的转录实现。最后，我们提供证据表明Snf/Swi复合物兼具转录激活与转录抑制功能，且两种调控模式均不依赖于对方的间接效应。本研究详情参见Sudarsanam P等人(2000)发表于《美国国家科学院院刊》（Proc Natl Acad Sci U S A）第97卷，第3364-3369页，关键词：其他。