Kokubo T, Swanson M J, Nishikawa J I, Hinnebusch A G, Nakatani Y
Laboratory of Molecular Growth Regulation, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
Mol Cell Biol. 1998 Feb;18(2):1003-12. doi: 10.1128/MCB.18.2.1003.
The Drosophila 230-kDa TFIID subunit (dTAF230) interacts with the DNA binding domain of TATA box-binding protein (TBP) which exists in the same complex. Here, we characterize the inhibitory domain in the yeast TAF145 (yTAF145), which is homologous to dTAF230. Mutation studies show that the N-terminal inhibitory region (residues 10 to 71) can be divided into two subdomains, I (residues 10 to 37) and II (residues 46 to 71). Mutations in either subdomain significantly impair function. Acidic residues in subdomain II are important for the interaction with TBP. In addition, yTAF145 interaction is impaired by mutating the basic residues on the convex surface of TBP, which are crucial for interaction with TFIIA. Consistently, TFIIA and yTAF145 bind competitively to TBP. A deletion of the inhibitory domain of yTAF145 leads to a temperature-sensitive growth phenotype. Importantly, this phenotype is suppressed by overexpression of the TFIIA subunits, indicating that the yTAF145 inhibitory domain is involved in TFIIA function.
果蝇230 kDa的TFIID亚基（dTAF230）与存在于同一复合物中的TATA盒结合蛋白（TBP）的DNA结合结构域相互作用。在此，我们对酵母TAF145（yTAF145）中与dTAF230同源的抑制结构域进行了表征。突变研究表明，N端抑制区域（第10至71位氨基酸残基）可分为两个亚结构域，亚结构域I（第10至37位氨基酸残基）和亚结构域II（第46至71位氨基酸残基）。任一亚结构域中的突变都会显著损害功能。亚结构域II中的酸性氨基酸残基对于与TBP的相互作用很重要。此外，通过突变TBP凸面上对与TFIIA相互作用至关重要的碱性氨基酸残基，yTAF145的相互作用会受到损害。一致地，TFIIA和yTAF145竞争性地结合TBP。yTAF145抑制结构域的缺失导致温度敏感的生长表型。重要的是，TFIIA亚基的过表达可抑制这种表型，表明yTAF145抑制结构域参与TFIIA的功能。
