Agarwal K, Baek K H, Jeon C J, Miyamoto K, Ueno A, Yoon H S
Department of Biochemistry, University of Chicago, Illinois 60637.
Biochemistry. 1991 Aug 6;30(31):7842-51. doi: 10.1021/bi00245a026.
The eukaryotic transcriptional factor TFIIS enhances transcript elongation by RNA polymerase II. Here we describe two functional domains in the 280 amino acid human TFIIS protein: residues within positions 100-230 are required for binding to polymerase, and residues 230-280, which form a zinc finger, are required in conjunction with the polymerase binding region for transcriptional stimulation. Interestingly, a mutant TFIIS with only the polymerase binding domain actually inhibits transcription, whereas a mutant in which the polymerase binding and zinc finger domains are separated by an octapeptide is only weakly active. The zinc finger itself has no effect on transcription, but in contrast to the wild-type protein, it binds to oligonucleotides. These findings suggest that TFIIS may interact with RNA polymerase II such that the normally masked zinc finger can specifically contact nucleotides in the transcription elongation zone at a position juxtaposed to the polymerization site.
真核转录因子TFIIS可增强RNA聚合酶II的转录延伸。在此，我们描述了280个氨基酸的人类TFIIS蛋白中的两个功能结构域：100 - 230位的残基是与聚合酶结合所必需的，而形成锌指结构的230 - 280位残基，与聚合酶结合区域一起是转录刺激所必需的。有趣的是，仅具有聚合酶结合结构域的突变型TFIIS实际上会抑制转录，而聚合酶结合结构域和锌指结构域被一个八肽隔开的突变体只有微弱的活性。锌指本身对转录没有影响，但与野生型蛋白不同的是，它能与寡核苷酸结合。这些发现表明，TFIIS可能与RNA聚合酶II相互作用，使得通常被掩盖的锌指能够在与聚合位点相邻的转录延伸区域特异性地接触核苷酸。
