Kerwin Christine L, Wykoff Dennis D
Department of Biology, Villanova University, Villanova, PA19085, USA.
Genetics. 2009 Jun;182(2):471-9. doi: 10.1534/genetics.109.101063. Epub 2009 Mar 30.
Comparative genomic analyses of Candida glabrata and Saccharomyces cerevisiae suggest many signal transduction pathways are highly conserved. Focusing on the phosphate signal transduction (PHO) pathway of C. glabrata, we demonstrate that components of the pathway are conserved and confirm the role of CgPHO81, CgPHO80, CgPHO4, and CgMSN5 in the PHO pathway through deletion analysis. Unlike S. cerevisiae, C. glabrata shows little dependence on the transcription factor, Pho2, for induction of phosphate-regulated genes during phosphate limitation. We show that the CgPho4 protein is necessary and sufficient for Pho2-independent gene expression; CgPho4 is capable of driving expression of PHO promoters in S. cerevisiae in the absence of ScPHO2. On the basis of the sequences of PHO4 in the hemiascomycetes and complementation analysis, we suggest that Pho2 dependence is a trait only observed in species closely related to S. cerevisiae. Our data are consistent with trans-regulatory changes in the PHO pathway via the transcription factor Pho4 as opposed to cis-regulatory changes (the promoter).
光滑念珠菌和酿酒酵母的比较基因组分析表明，许多信号转导途径高度保守。聚焦于光滑念珠菌的磷酸信号转导（PHO）途径，我们证明该途径的组分是保守的，并通过缺失分析证实了CgPHO81、CgPHO80、CgPHO4和CgMSN5在PHO途径中的作用。与酿酒酵母不同，在磷限制期间，光滑念珠菌对转录因子Pho2诱导磷调节基因的依赖性很小。我们表明，CgPho4蛋白对于不依赖Pho2的基因表达是必要且充分的；在没有ScPHO2的情况下，CgPho4能够驱动酿酒酵母中PHO启动子的表达。基于半子囊菌中PHO4的序列和互补分析，我们认为对Pho2的依赖性是仅在与酿酒酵母密切相关的物种中观察到的一种特性。我们的数据与通过转录因子Pho4的PHO途径中的反式调节变化一致，而不是顺式调节变化（启动子）。
