Thomas D, Kuras L, Barbey R, Cherest H, Blaiseau P L, Surdin-Kerjan Y
Centre de Génétique Moléculaire, Centre National de la Recherche Scientifique, Gif-sur-Yvette, France.
Mol Cell Biol. 1995 Dec;15(12):6526-34. doi: 10.1128/MCB.15.12.6526.
A specific repression mechanism regulates the biosynthesis of sulfur amino acids in Saccharomyces cerevisiae. When the intracellular S-adenosylmethionine (AdoMet) concentration increases, transcription of the sulfur genes is repressed. Using a specific reporter system, we have isolated mutations impairing the AdoMet-mediated transcriptional regulation of the sulfur network. These mutations identified a new gene, MET30, and were shown to also affect the regulation of the methyl cycle. The MET30 gene was isolated and sequenced. Sequence analysis reveals that Met30p contains five copies of the WD40 motif within its carboxy-terminal part, like the yeast transcriptional repressors Hir1p and Tup1p. We identified one target of Met30p as Met4p, a transcriptional activator regulating the sulfate assimilation pathway. By the two-hybrid method, we showed that Met30p interacts with Met4p and identified a region of Met4p involved in this interaction. Further analysis reveals that expression of Met30p is essential for cell viability.
一种特定的抑制机制调控酿酒酵母中硫氨基酸的生物合成。当细胞内S-腺苷甲硫氨酸（AdoMet）浓度增加时，硫基因的转录受到抑制。利用一种特定的报告系统，我们分离出了损害AdoMet介导的硫代谢网络转录调控的突变。这些突变鉴定出一个新基因MET30，并且显示也影响甲基循环的调控。MET30基因被分离并测序。序列分析表明，Met30p在其羧基末端部分含有五个WD40基序拷贝，类似于酵母转录抑制因子Hir1p和Tup1p。我们鉴定出Met30p的一个靶标是Met4p，Met4p是一种调控硫酸盐同化途径的转录激活因子。通过双杂交方法，我们表明Met30p与Met4p相互作用，并鉴定出Met4p中参与这种相互作用的一个区域。进一步分析表明，Met30p的表达对细胞活力至关重要。
