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酵母调控因子ＰＨＯ８５是一个依赖于细胞周期蛋白（ｃｙｃｌｉｎ）的蛋白激酶（ＣＤＫ），参与对细胞周期和酸性磷酸酯酶基因表达的调控。以ＰＨＯ８５为靶分子，利用酵母双杂交（ｔｗｏ－ｈｙｂｒｉｄ）系统从酵母的染色体基因文库中克隆到了一个新的与ＰＨＯ８５相结合的蛋白因子的基因，将此蛋白质命名为ＰＡＰ１（ＰＨＯ８５ａｓｓｏｃｉａｔｅｄｐｒｏｔｅｉｎ）。克隆了包含ＰＡＰ１全部编码区以及上下游调控序列的２．０ｋｂ的基因，并进行了序列测定。ＰＡＰ１基因编码区全长８５５ｂｐ，编码一个２８５个氨基酸的蛋白质。同源性比较表明，ＰＡＰ１蛋白的羧端半分子包含一个细胞周期蛋白保守的结构域（１５０～２６３），与ＰＨＯ８０的保守区（６７～１６８）的同源性为６３％。而ＰＡＰ１蛋白的Ｎ端半分子富含ＰＥＳＴ序列，这种序列使蛋白质的稳定性降低。双杂交实验证明ＰＡＰ１蛋白的全长和Ｃ端（９９～２８５）都能同ＰＨＯ８５相互结合。构建了在ＰＬ启动子控制下的ＰＡＰ１的表达质粒，并在大肠杆菌ＢＬ２１（ＤＥ３）ｐＬｙｓＳ中进行了表达。经４２℃热诱导，得到了分子量约为３２ｋＤ的蛋白质电泳条带，与ＰＡＰ１的计算分子量相符。其Ｎ端氨基酸序列与预测相符。这一表达产物经鉴?
Yeast Regulator PHO85 is a cyclin-dependent protein kinase (CDK) involved in the regulation of cell cycle and acid phosphatase gene expression. Using PHO85 as a target, a new gene of PHO85-binding protein was cloned from the yeast chromosomal gene library by yeast two-hybrid system. The protein was named PAP1 (PHO85associatedprotein). The 2.0kb gene containing the entire coding region of PAP1 and upstream and downstream regulatory sequences was cloned and sequenced. The PAP1 gene coding region is 855bp in length and encodes a 285 amino acid protein. Homology comparison showed that the carboxyl terminal half of PAP1 contained a cyclin conserved domain (150 ~ 263), which shared 63% homology with the conserved region of PHO80 (67 ~ 168). However, the N-terminal half-molecule of PAP1 protein is rich in PEST sequence, which reduces the stability of the protein. Two-hybrid experiments show that the full-length and C-terminal of PAP1 protein (99-285) can bind to PHO85. The expression plasmid for PAP1 under the control of the PL promoter was constructed and expressed in E. coli BL21 (DE3) pLysS. After 42 ℃ thermal induction, a molecular weight of about 32kD protein electrophoresis bands, consistent with the calculated molecular weight of PAP1. Its N-terminal amino acid sequence is consistent with the prediction. This expression product Kam Kam?