Takahata Shinya, Kasahara Koji, Kawaichi Masashi, Kokubo Tetsuro
Division of Molecular and Cellular Biology, Graduate School of Integrated Science, Yokohama City University, Yokohama 230-0045, Japan.
Mol Cell Biol. 2004 Apr;24(8):3089-99. doi: 10.1128/MCB.24.8.3089-3099.2004.
The general transcription factor TFIID is composed of TATA-binding protein (TBP) and 14 TBP-associated factors (TAFs). TFIID mediates the transcriptional activation of a subset of eukaryotic promoters. The N-terminal domain (TAND) of TAF1 protein (Taf1p) inhibits TBP by binding to its concave and convex surfaces. This study examines the role of the TAND in transcriptional regulation and tests whether the TAND is an autonomous regulator of TBP. The TAND binds to and regulates TBP function when it is fused to the amino or carboxy terminus of Taf1p, the amino or carboxy terminus of Taf5p, or the amino terminus of Taf11p. However, a carboxy-terminal fusion of the TAND and Taf11p is not compatible with several other TAF proteins, including Taf1p, in the TFIID complex. These results indicate that there is no or minimal geometric constraint on the ability of the TAND to function normally in transcriptional regulation as long as TFIID assembly is secured.
通用转录因子TFIID由TATA结合蛋白（TBP）和14种TBP相关因子（TAFs）组成。TFIID介导真核生物启动子子集的转录激活。TAF1蛋白（Taf1p）的N端结构域（TAND）通过结合TBP的凹面和凸面来抑制TBP。本研究探讨了TAND在转录调控中的作用，并测试TAND是否为TBP的自主调节因子。当TAND与Taf1p的氨基或羧基末端、Taf5p的氨基或羧基末端或Taf11p的氨基末端融合时，它会结合并调节TBP的功能。然而，TAND与Taf11p的羧基末端融合与TFIID复合物中的其他几种TAF蛋白（包括Taf1p）不兼容。这些结果表明，只要TFIID组装得到保证，TAND在转录调控中正常发挥功能的能力就不存在或存在最小的几何限制。
