Bennett Richard J, Johnson Alexander D
Department of Microbiology and Immunology, University of California San Francisco, San Francisco, CA 94143, USA.
Mol Microbiol. 2006 Oct;62(1):100-19. doi: 10.1111/j.1365-2958.2006.05367.x.
Although traditionally classified as asexual, the human fungal pathogen Candida albicans can undergo highly efficient mating. A key component of this mating is the response to pheromone, which is mediated by a conserved kinase cascade that transduces the signal from the pheromone receptor to a transcriptional response in the nucleus. In this paper we show (i) that the detailed response of C. albicans to the alpha pheromone differs among clinical isolates, (ii) that the response depends critically on nutritional conditions, (iii) that the entire response is mediated by the Ste2 receptor, and (iv) that, in terms of genes induced, the response to alpha pheromone in C. albicans shows only marginal overlap with the response in Saccharomyces cerevisiae. We further investigated the nutritional control of pheromone induction and identify the GPA2 gene as a critical component. We found that Deltagpa2/Deltagpa2 mutants are hypersensitive to pheromone and, unlike wild-type strains, show efficient cell cycle arrest (including the formation of characteristic halos on solid medium) in response to mating pheromone. These results indicate that C. albicans, like several other fungal species but unlike S. cerevisiae, integrates signals from a nutrient-sensing pathway with those of the pheromone response MAP kinase pathway to generate the final transcriptional response.
尽管传统上被归类为无性繁殖，但人类真菌病原体白色念珠菌能够进行高效交配。这种交配的一个关键组成部分是对信息素的反应，它由一个保守的激酶级联介导，该级联将信号从信息素受体传递到细胞核中的转录反应。在本文中，我们表明：（i）白色念珠菌对α信息素的详细反应在临床分离株中存在差异；（ii）该反应严重依赖营养条件；（iii）整个反应由Ste2受体介导；（iv）就诱导的基因而言，白色念珠菌对α信息素的反应与酿酒酵母中的反应仅存在少量重叠。我们进一步研究了信息素诱导的营养控制，并确定GPA2基因为关键组成部分。我们发现Δgpa2/Δgpa2突变体对信息素高度敏感，并且与野生型菌株不同，它们在响应交配信息素时表现出有效的细胞周期停滞（包括在固体培养基上形成特征性晕圈）。这些结果表明，白色念珠菌与其他几种真菌物种一样，但与酿酒酵母不同，它将来自营养感应途径的信号与信息素反应丝裂原活化蛋白激酶途径的信号整合起来，以产生最终的转录反应。
