Weinzierl R O, Ruppert S, Dynlacht B D, Tanese N, Tjian R
Howard Hughes Medical Institute, Department of Molecular and Cell Biology, University of California at Berkeley 94720.
EMBO J. 1993 Dec 15;12(13):5303-9. doi: 10.1002/j.1460-2075.1993.tb06226.x.
Regulation of transcription initiation by RNA polymerase II requires TFIID, a multisubunit complex composed of the TATA binding protein (TBP) and at least seven tightly associated factors (TAFs). Some TAFs act as direct targets or coactivators for promoter-specific activators while others serve as interfaces for TAF-TAF interactions. Here, we report the molecular cloning, expression and characterization of Drosophila dTAFII60 and its human homolog, hTAFII70. Recombinant TAFII60/70 binds weakly to TBP and tightly to the largest subunit of TFIID, TAFII250. In the presence of TAFII60/70, TBP and TAFII250, a stable ternary complex is formed. Both the human and Drosophila proteins directly interact with another TFIID subunit, dTAFII40. Our findings reveal that Drosophila TAFII60 and human TAFII70 share a high degree of structural similarity and that their interactions with other subunits of TFIID are conserved.
RNA聚合酶II对转录起始的调控需要TFIID，它是一种多亚基复合物，由TATA结合蛋白（TBP）和至少七个紧密相关的因子（TAFs）组成。一些TAFs作为启动子特异性激活因子的直接靶点或共激活因子，而其他TAFs则作为TAF-TAF相互作用的界面。在此，我们报道了果蝇dTAFII60及其人类同源物hTAFII70的分子克隆、表达及特性。重组TAFII60/70与TBP结合较弱，而与TFIID的最大亚基TAFII250结合紧密。在TAFII60/70、TBP和TAFII250存在的情况下，会形成稳定的三元复合物。人类和果蝇的这种蛋白都直接与另一个TFIID亚基dTAFII40相互作用。我们的研究结果表明，果蝇TAFII60和人类TAFII70具有高度的结构相似性，并且它们与TFIID其他亚基的相互作用是保守的。
