Ramer S W, Davis R W
Department of Biochemistry, Stanford University School of Medicine, CA 94305.
Proc Natl Acad Sci U S A. 1993 Jan 15;90(2):452-6. doi: 10.1073/pnas.90.2.452.
This work reports the identification, characterization, and nucleotide sequence of STE20, a newly discovered gene involved in the Saccharomyces cerevisiae mating response pathway, to date one of the best understood signal transduction pathways. STE20 encodes a putative serine/threonine-specific protein kinase with a predicted molecular mass of 102 kDa. Its expression pattern is similar to that of several other protein kinases in the mating response pathway. Deletion of the kinase domain of STE20 causes sterility in both haploid mating types. This sterility can be partially suppressed by high-level production of STE12 but is not suppressible by high levels of STE4 or a dominant STE11 truncation allele. A truncation allele of STE20 was isolated that can activate the mating response pathway in the absence of exogenous mating pheromone. This allele causes dominant growth arrest that cannot be suppressed by deletions of STE4, STE5, STE7, STE11, or STE12. The allele is able to suppress the mating defect of a strain in which the STE20 kinase domain has been deleted, but not the mating defects of strains carrying mutations in STE4, STE5, STE7, STE11, or STE12.
这项研究报告了STE20基因的鉴定、特征分析及核苷酸序列，STE20是新发现的参与酿酒酵母交配反应途径的基因，该途径是目前理解最为透彻的信号转导途径之一。STE20编码一种假定的丝氨酸/苏氨酸特异性蛋白激酶，预测分子量为102 kDa。其表达模式与交配反应途径中其他几种蛋白激酶的表达模式相似。缺失STE20的激酶结构域会导致两种单倍体交配型均不育。这种不育可被STE12的高水平表达部分抑制，但不能被STE4的高水平表达或显性STE11截短等位基因抑制。分离出一个STE20截短等位基因，它在没有外源交配信息素的情况下能激活交配反应途径。该等位基因导致显性生长停滞，且不能被STE4、STE5、STE7、STE11或STE12的缺失所抑制。该等位基因能够抑制STE20激酶结构域缺失菌株的交配缺陷，但不能抑制携带STE4、STE5、STE7、STE11或STE12突变菌株的交配缺陷。
