Stanway C A, Chambers A, Kingsman A J, Kingsman S M
Department of Biochemistry, Oxford University, South Parks Road, Oxford.
Nucleic Acids Res. 1989 Nov 25;17(22):9205-18. doi: 10.1093/nar/17.22.9205.
The upstream activator (UAS) of the yeast PGK gene comprises three different sequence elements. These are 1) a region of strong protein binding called the YFP, 2) three repeats of the motif CTTCC and 3) an essential activator core (AC) sequence that binds the protein RAP1. To assess the function of each of these elements in transcriptional activation we have inserted them individually and in various combinations into a PGK mini-promoter. This comprises only the transcription initiation elements from the PGK promoter and is inactive in the absence of activator sequences. None of the individual sequence elements was capable of activating the mini-promoter. However either the YFP or the CTTCC boxes in conjunction with the AC box resulted in efficient expression. Transcription levels were not however as high as when all three elements were inserted. These data suggest that the efficiency of PGK transcription depends upon the interactions between three different sequences. Furthermore while RAP1 per se is not a transcriptional activator it can associate promiscuously with other factors to create a functional transcription complex.
酵母磷酸甘油酸激酶（PGK）基因的上游激活序列（UAS）由三个不同的序列元件组成。它们分别是：1）一个名为YFP的强蛋白结合区域；2）基序CTTCC的三个重复序列；3）一个与RAP1蛋白结合的必需激活核心（AC）序列。为了评估这些元件中每一个在转录激活中的功能，我们将它们单独或以各种组合形式插入到一个PGK微型启动子中。该微型启动子仅包含来自PGK启动子的转录起始元件，在没有激活序列的情况下是无活性的。单个序列元件均不能激活微型启动子。然而，YFP或CTTCC框与AC框结合可导致高效表达。不过，转录水平不如插入所有三个元件时高。这些数据表明，PGK转录的效率取决于三个不同序列之间的相互作用。此外，虽然RAP1本身不是转录激活因子，但它可以与其他因子随意结合以形成功能性转录复合物。
