Colgan J, Manley J L
Department of Biological Sciences, Columbia University, New York, New York 10027.
Genes Dev. 1992 Feb;6(2):304-15. doi: 10.1101/gad.6.2.304.
We have studied the effect of exogenous expression of the basal transcription factor TFIID on the activities of several different TATA-containing and TATA-lacking promoters. Overexpression of TFIID from a transfected plasmid in Drosophila Schneider cells resulted in substantial concentration-dependent increases in expression from a cotransfected minimal TATA-containing promoter. Overexpression of TFIID activated expression from all TATA-containing promoters tested, with the maximum level of activation being inversely proportional to the strength of the promoter. In contrast, expression from TATA-less promoters was not enhanced, and could in fact be reduced, by increased expression of TFIID. Consistent with these findings overexpression of TFIID had opposite effects on Sp1-mediated activation observed from minimal synthetic promoters consisting of Sp1-binding sites and either a TATA box or initiator element. We discuss the significance of these results in terms of the role of TFIID in the initiation of transcription and as a possible regulatory target for expression from TATA-containing promoters, as well as the role TFIID may play in expression from TATA-less promoters.
我们研究了基础转录因子TFIID的外源性表达对几种不同的含TATA盒和不含TATA盒启动子活性的影响。在果蝇施耐德细胞中，转染质粒中外源性TFIID的过表达导致共转染的最小含TATA盒启动子的表达呈浓度依赖性显著增加。TFIID的过表达激活了所有测试的含TATA盒启动子的表达，最大激活水平与启动子强度成反比。相比之下，TFIID表达的增加并未增强不含TATA盒启动子的表达，实际上反而可能降低其表达。与这些发现一致，TFIID的过表达对由Sp1结合位点以及TATA盒或起始元件组成的最小合成启动子所观察到的Sp1介导的激活具有相反的影响。我们从TFIID在转录起始中的作用、作为含TATA盒启动子表达的可能调控靶点以及TFIID在不含TATA盒启动子表达中可能发挥的作用等方面讨论了这些结果的意义。
