Graham I R, Chambers A
Department of Genetics, University of Nottingham, Queen's Medical Centre, UK.
Mol Microbiol. 1994 Jun;12(6):931-40. doi: 10.1111/j.1365-2958.1994.tb01081.x.
The Saccharomyces cerevisiae RAP1 protein (Rap1p) is a key multifunctional transcription factor. Using gel retardation analysis, four binding sites for Rap1p have been identified within the promoter of the RAP1 gene. These sites are located downstream of a binding site for the transcription factor Reb1p. The Reb1p site and an associated AT-rich region are important for transcriptional activation, but deletion of three of the Rap1p-binding sites had little effect on promoter activity. The activity of the RAP1 promoter has been analysed in a yeast strain (YDS410) that contains a temperature-sensitive mutation in the RAP1 gene. This mutation renders the DNA-binding activity of Rap1p temperature dependent. When YDS410 was grown at a semi-permissive temperature (30 degrees C), the activity of the RAP1 promoter increased by approximately 170%, compared with the same strain grown at the permissive temperature (25 degrees C). A RAP1 promoter in which three of the four Rap1p-binding sites had been deleted, showed only a small increase in activity in the same experiment. These data confirm that Rap1p is not required for activation of the RAP1 gene, and suggest a role for Rap1p in negative autoregulation.
酿酒酵母RAP1蛋白（Rap1p）是一种关键的多功能转录因子。通过凝胶阻滞分析，在RAP1基因启动子内已鉴定出四个Rap1p结合位点。这些位点位于转录因子Reb1p结合位点的下游。Reb1p位点及相关的富含AT区域对转录激活很重要，但缺失三个Rap1p结合位点对启动子活性影响不大。已在一株酵母菌株（YDS410）中分析了RAP1启动子的活性，该菌株的RAP1基因存在温度敏感突变。此突变使Rap1p的DNA结合活性具有温度依赖性。当YDS410在半允许温度（30℃）下生长时，与在允许温度（25℃）下生长的同一菌株相比，RAP1启动子的活性增加了约170%。在同一实验中，四个Rap1p结合位点中的三个已被删除的RAP1启动子，其活性仅略有增加。这些数据证实Rap1p对于RAP1基因的激活不是必需的，并提示Rap1p在负向自调节中发挥作用。
