Liljelund P, Ingles C J, Greenblatt J
Banting and Best Department of Medical Research, University of Toronto, Ontario, Canada.
Mol Gen Genet. 1993 Dec;241(5-6):694-9. doi: 10.1007/BF00279913.
The acidic transcriptional activation domain of the Herpes simplex virus protein VP16 has been shown to bind directly to both the TATA box-binding factor TBP and the general initiation factor TFIIB. Using DNase I footprinting assays, we have shown here that the VP16 activation domain qualitatively alters binding of Saccharomyces cerevisiae TBP to a TATA sequence in DNA. The effect of VP16 on promoter binding by TBP was reduced by mutations in VP16 known to reduce transactivation and could not be overcome by increasing the amount of TBP used in the footprinting assays. However, the association of yeast TFIIA with TBP on the promoter reversed the VP16-mediated effect and restored normal binding of TBP to the promoter. We suggest that VP16 induces a conformational change in TBP which alters its binding to promoter DNA, and that this effect of VP16 is suppressed by TFIIA.
单纯疱疹病毒蛋白VP16的酸性转录激活结构域已被证明可直接与TATA盒结合因子TBP和通用起始因子TFIIB结合。通过DNA酶I足迹分析，我们在此表明VP16激活结构域定性地改变了酿酒酵母TBP与DNA中TATA序列的结合。已知可降低反式激活作用的VP16突变会降低VP16对TBP与启动子结合的影响，并且在足迹分析中增加TBP的用量也无法克服这种影响。然而，酵母TFIIA与启动子上的TBP的结合逆转了VP16介导的效应，并恢复了TBP与启动子的正常结合。我们认为，VP16诱导TBP发生构象变化，从而改变其与启动子DNA的结合，并且TFIIA可抑制VP16的这种作用。
