Recognition of galactose by a scaffold protein recruits a transcriptional activator for the GAL regulon induction in Candida albicans.
Recognition of galactose by a scaffold protein recruits a transcriptional activator for the GAL regulon induction in Candida albicans.
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作者：
Sun X;Yu J;Zhu C;Mo X;Sun Q;Yang D;Su C;Lu Y
酵母的GAL途径长期以来一直是理解真核代谢途径调控模式演变的模型系统。虽然Gal4模式已经在酵母科分支中得到了很好的表征，但对其他酵母中Gal4途径的调节知之甚少。在这里，我们发现Rep1，一个类似Ndt80的家族转录因子，在共生致病真菌白色念珠菌中作为半乳糖感受器。它是在半乳糖存在的情况下独立于半乳糖基因启动子出现的。REP1通过直接的物理作用识别半乳糖。这种相互作用的最终结果是转录激活剂CGa1(假丝酵母半乳糖基因激活剂，orf19.4959)的招募，并进行GAL基因的转录。REP1和CGa1在CTG物种中保守。REP1本身并不具有转录活性。相反，它提供了一个脚手架来招募不同的转录调控因子。REP1-CGa1调控模式代表了真菌中网络重新布线的新例子，这为白色念珠菌如何进化转录程序以定植不同的宿主生态位提供了洞察。
The GAL pathway of yeasts has long served as a model system for understanding of how regulatory mode of eukaryotic metabolic pathways evolves. While Gal4 mode has been well-characterized in Saccharomycetaceae clade, little is known about the regulation of the GAL pathway in other yeasts. Here, we find that Rep1, a Ndt80-like family transcription factor, serves as a galactose sensor in the commensal-pathogenic fungus Candida albicans. It is presented at the GAL gene promoters independent of the presence of galactose. Rep1 recognizes galactose via a direct physical interaction. The net result of this interaction is the recruitment of a transcriptional activator Cga1 (Candida galactose gene activator, orf19.4959) and transcription of the GAL genes proceeds. Rep1 and Cga1 are conserved across the CTG species. Rep1 itself does not possess transcriptional activity. Instead, it provides a scaffold to recruit different factors for transcriptional regulation. Rep1-Cga1 mode of regulation represents a new example of network rewiring in fungi, which provides insight into how C. albicans evolves transcriptional programs to colonize diverse host niches.