Upstream stimulatory factor 2 stimulates transcription through an initiator element in the mouse cytochrome c oxidase subunit Vb promoter.
Upstream stimulatory factor (USF) is a basic helix-loop-helix-leucine zipper transcription factor that plays an important role in transcriptional activation and cell proliferation. In this article, we demonstrate that the mouse cytochrome c oxidase subunit Vb gene (Cox5b) can be transactivated by ectopic expression of USF2 through an initiator (Inr) element in the core promoter. Importantly, using a dominant-negative mutant of USF2, we demonstrate the role of endogenous USF2 proteins in the transcriptional activation of the Cox5b Inr. Domains of USF2 encoded by exon 4, exon 5 and the USF-specific region are important for maximum activation of the Cox5b Inr. Using the adenovirus E1A oncoprotein, we show that p300/CBP acts as a coactivator in the USF2-dependent activation of the Cox5b Inr. We also demonstrate that although expression of multifunctional regulatory factor, Yin Yang 1 (YY1), can stimulate transcription of the Cox5b Inr to a modest extent, expression of YY1 together with USF2 greatly reduces the level of activation of the Cox5b Inr. Furthermore, we show that the transcription factor, Sp1, represses both the YY1- and the USF2-dependent activation of the Cox5b Inr, indicating competition among Sp1, YY1, and USF2.
Breen
G A
GA
Department of Molecular and Cell Biology, The University of Texas at Dallas, P.O. Box 830688, Richardson, TX 75083-0688, USA. breen@utdallas.edu
Jordan
E M
EM
D000818:Animals; D004268:DNA-Binding Proteins / Q000235:genetics; D050881:E1A-Associated p300 Protein; D003576:Electron Transport Complex IV / Q000737:chemistry / Q000235:genetics*; D004789:Enzyme Activation / Q000235:genetics; D050981:Erythroid-Specific DNA-Binding Factors; D051379:Mice; D009154:Mutation; D009687:Nuclear Proteins / Q000378:metabolism; D011401:Promoter Regions, Genetic; D016329:Sp1 Transcription Factor / Q000235:genetics; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic; D051720:Upstream Stimulatory Factors; D050986:YY1 Transcription Factor
D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D009687:Nuclear Proteins; D016329:Sp1 Transcription Factor; D015534:Trans-Activators; D014157:Transcription Factors; D051720:Upstream Stimulatory Factors; C497183:Usf1 protein, mouse; C497186:Usf2 protein, mouse; D050986:YY1 Transcription Factor; C494699:Yy1 protein, mouse; D003576:Electron Transport Complex IV; D050881:E1A-Associated p300 Protein; C494361:Ep300 protein, mouse