酵母PHO2与PHO4蛋白的激活活性的分析及两者的相互作用  

Analysis of Activation Activity of Yeast PHO2, PHO4 Protein and Their Interaction

作　　者：杨军[1] 吴健生[1] 敖世洲[1] 

机构地区：[1]中国科学院上海生物化学研究所分子生物学国家重点实验室

出　　处：《生物化学与生物物理学报》1997年第2期122-128,共7页

摘　　要：ＰＨＯ２与ＰＨＯ４是酵母ＰＨＯ５基因的两个正调控因子。本文发现，ＰＨＯ２与酵母转录因子ＧＡＬ４的ＤＮＡ结合功能域融合后就能激活报道基因ｌａｃＺ的表达，其激活活力受高低磷影响，表明ＰＨＯ２蛋白上存在酸性转录激活区。ＰＨＯ２蛋白上酸性氨基酸丰富的２８７～３２６肽段并非ＰＨＯ２的激活区。在ＰＨＯ２蛋白上２３０位Ｓｅｒ处于磷酸化状态ＰＨＯ２才有激活作用，表明了这一磷酸化位点可能与ＰＨＯ２的转录激活能力有关。ＰＨＯ４蛋白与ＧＡＬ４ＤＮＡ结合功能域融合后，也能激活ｌａｃＺ的表达，ＰＨＯ４Ｎ端酸性氨基酸丰富区１～９７肽段是其转录激活区。采用ｔｗｏ－ｈｙｂｒｉｄ方法，证明了ＰＨＯ２与ＰＨＯ４之间存在相互作用，这种相互作用影响它们的转录激活能力。Both PHO2 and PHO4 are positive regulatory factors of yeast PHO5 gene. Here we show that the PHO2 fused to yeast transcriptional factor GAL4 DNA binding domain activates the expression of the reporter gene (lacZ), and the lacZ activities were regulated by Pi concentration, therefore it could be suggested that there are acidic activation domains on the PHO2 protein. Acidic amino acid rich region of 287-326aa in PHO2 is not a transcriptional activation domain. PHO2 maintaind its activation activity only if Ser230 is phosphorylated, thus the phosphorylated site may play a key role in the transcriptional activation function of PHO2. PHO4 fused to the GAL4 DNA binding domain also activates the expression of lacZ. A segment of 1-97aa at its N termimal is responsible for the transcriptional activation acivity. A two hybrid assay reveals that there exists interaction between PHO2 and PHO4 protein, and the interaction affects their transcriptional activation function.

关 键 词：蛋白 酵母 PHO2 PHO4 

分 类 号：Q949.326.1[生物学—植物学]