Reese J C, Apone L, Walker S S, Griffin L A, Green M R
Howard Hughes Medical Institute, University of Massachusetts Medical Center, Worcester 01605.
Nature. 1994 Oct 6;371(6497):523-7. doi: 10.1038/371523a0.
In higher eukaryotes the RNA polymerase II transcription factor TFIID is composed of a TATA-box-binding protein (TBP) and a set of tightly bound polypeptides, designated TBP-associated factors (TAFIIS). One or more TAFIIS are coactivators that are required for activated but not basal transcription. The eukaryotic transcription machinery is highly conserved and it is therefore puzzling that TAFIIS have not been identified in yeast. Here we use TBP as a protein-affinity ligand to isolate from yeast a multisubunit complex that is required specifically for activated transcription by RNA polymerase II. Microsequence analysis and cloning of two subunits of this complex reveal that they are the homologues of known mammalian and Drosophila TAFIIS. The genes encoding these two yeast TAFIIS are essential, suggesting that activated transcription is required for viability of Saccharomyces cerevisiae.
在高等真核生物中，RNA聚合酶II转录因子TFIID由一个TATA框结合蛋白（TBP）和一组紧密结合的多肽组成，这些多肽被称为TBP相关因子（TAFIIs）。一个或多个TAFIIs是共激活因子，它们是激活转录而非基础转录所必需的。真核转录机制高度保守，因此酵母中尚未鉴定出TAFIIs这一点令人困惑。在这里，我们使用TBP作为蛋白质亲和配体，从酵母中分离出一种多亚基复合物，它是RNA聚合酶II激活转录所特需的。对该复合物的两个亚基进行微序列分析和克隆表明，它们是已知的哺乳动物和果蝇TAFIIs的同源物。编码这两个酵母TAFIIs的基因是必需的，这表明激活转录对于酿酒酵母的生存能力是必需的。
