Lemire J M, Willcocks T, Halvorson H O, Bostian K A
Mol Cell Biol. 1985 Aug;5(8):2131-41. doi: 10.1128/mcb.5.8.2131-2141.1985.
We examined the genetic system responsible for transcriptional regulation of repressible acid phosphatase (APase; orthophosphoric-monoester phosphohydrolase [acid optimum, EC 3.1.3.2]) in Saccharomyces cerevisiae at the molecular level by analysis of previously isolated and genetically well-defined regulatory gene mutants known to affect APase expression. These mutants identify numerous positive- (PHO4, PHO2, PHO81) and negative-acting (PHO80, PHO85) regulatory loci dispersed throughout the yeast genome. We showed that the interplay of these positive and negative regulatory genes occurs before or during APase gene transcription and that their functions are all indispensible for normal regulation of mRNA synthesis. Biochemical evidence suggests that the regulatory gene products they encode are expressed constitutively. More detailed investigation of APase synthesis is a conditional PHO80(Ts) mutant indicated that neither PHO4 nor any other protein factor necessary for APase mRNA synthesis is transcriptionally regulated by PHO80. Moreover, in the absence of PHO80, the corepressor, presumed to be a metabolite of Pi, did not inhibit their function in the transcriptional activation of APase.
我们通过分析先前分离出的、遗传特性明确且已知会影响酸性磷酸酶（APase；正磷酸单酯磷酸水解酶[最适酸性，EC 3.1.3.2]）表达的调控基因突变体，在分子水平上研究了酿酒酵母中负责可阻遏酸性磷酸酶转录调控的遗传系统。这些突变体鉴定出了众多分布于整个酵母基因组中的正向（PHO4、PHO2、PHO81）和负向作用（PHO80、PHO85）调控位点。我们发现这些正向和负向调控基因的相互作用发生在APase基因转录之前或期间，并且它们的功能对于mRNA合成的正常调控都是不可或缺的。生化证据表明它们所编码的调控基因产物是组成型表达的。对APase合成的更详细研究是在一个条件性PHO80（Ts）突变体中进行的，结果表明PHO4或APase mRNA合成所需的任何其他蛋白质因子都不受PHO80的转录调控。此外，在没有PHO80的情况下，假定为Pi代谢产物的辅阻遏物并不会抑制它们在APase转录激活中的功能。
