Furter-Graves E M, Furter R, Hall B D
Department of Genetics, University of Washington, Seattle 98195.
Mol Cell Biol. 1991 Aug;11(8):4121-7. doi: 10.1128/mcb.11.8.4121-4127.1991.
In a genetic selection for Saccharomyces cerevisiae genes involved in transcription start site specification, two mutant genes which restore alcohol dehydrogenase activity to a functionally defective S. pombe ADH gene were recovered. Examination of S. pombe ADH initiation sites showed that mutations in the SHI gene shift the location of the transcription initiation window closer to TATA. The shi mutant also affected initiation site selection for two S. cerevisiae genes that were tested. For H2B mRNA, initiation occurred in the shi mutant at a series of initiation sites located 43 to 80 bp 3' of the histone H2B TATA sequence and at the usual initiation sites 102 and 103 bp downstream of the TATA sequence. Weakly used initiation sites ranging from 51 to 80 bp downstream of the TATA sequence were observed for the S. cerevisiae ADH1 gene in shi strains, in addition to the normal ADH1 initiation sites 89 and 99 bp from the TATA sequence. Restoration of function to the defective S. pombe ADH gene occurs only when this gene contains a TATA sequence; a single-base-pair TATA-to-TAGA change is sufficient to prevent this restoration of function. Genetic mapping placed the SHI locus on the left arm of chromosome VII, 22.3 centimorgans from cyh2; it does not correspond to any previously mapped gene.
在对参与转录起始位点确定的酿酒酵母基因进行的遗传筛选中，回收了两个能使功能缺陷型粟酒裂殖酵母ADH基因恢复乙醇脱氢酶活性的突变基因。对粟酒裂殖酵母ADH起始位点的检查表明，SHI基因中的突变会使转录起始窗口的位置更靠近TATA。shi突变体还影响了所测试的两个酿酒酵母基因的起始位点选择。对于H2B mRNA，在shi突变体中，起始发生在一系列位于组蛋白H2B TATA序列下游43至80 bp处的起始位点以及TATA序列下游102和103 bp处的通常起始位点。在shi菌株中，除了距TATA序列89和99 bp处的正常ADH1起始位点外，还观察到粟酒裂殖酵母ADH1基因在TATA序列下游51至80 bp处的弱使用起始位点。只有当缺陷型粟酒裂殖酵母ADH基因包含TATA序列时，其功能才能恢复；单个碱基对的TATA到TAGA变化足以阻止这种功能恢复。遗传定位将SHI基因座定位于染色体VII的左臂上，距离cyh2有22.3厘摩；它与任何先前定位的基因都不对应。
