cAMP-independent activation of the adenovirus type 12 E2 promoter correlates with the recruitment of CREB-1/ATF-1, E1A(12S), and CBP to the E2-CRE.
Expression of the transcription unit early region 2 (E2) is of crucial importance for adenoviruses because this region encodes proteins essential for viral replication. Here, we demonstrate that the E1A(12S) protein of the oncogenic adenovirus serotype 12 activates the E2 promoter in dependence of the N terminus and the conserved region 1. Activation is mediated through a cAMP-response element that is bound by CREB-1 and ATF-1. Moreover, the Ad12 E2 promoter is inducible by protein kinase A and repressed by either a dominant-negative cAMP-response element-binding protein (CREB) mutant or the highly specific protein kinase A inhibitor protein underscoring the participation of CREB-1/ATF-1 in promoter activation. E1A(12S) binds to CREB-1 and ATF-1 in dependence of the N terminus and CR1 and is recruited to the E2 cAMP-response element through both cellular transcription factors. Most interestingly, point mutations revealed that E1A(12S) domains essential for binding to CREB-1/ATF-1 and for activation of the Ad12 E2 promoter are also essential for binding to the CREB-binding protein. Due to these data and results obtained in DNA-dependent protein-protein interaction assays, we propose a model in which the cAMP-independent activation of the Ad12 E2 promoter is mediated through a ternary complex consisting of CREB-1/ATF-1, E1A(12S), and CREB-binding protein, which assembles on the E2 cAMP-response element.
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Institute of Molecular Biology (Cancer Research), University of Essen Medical School, Hufelandstrasse 55, 45122 Essen, Germany.
Lipinski
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KS
Esche
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Brockmann
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D051697:Activating Transcription Factor 1; D000256:Adenoviridae / Q000235:genetics / Q000254:growth & development; D017500:Adenovirus E1A Proteins / Q000378:metabolism; D017502:Adenovirus E2 Proteins / Q000235:genetics*; D001483:Base Sequence; D050882:CREB-Binding Protein; D017124:Conserved Sequence; D000242:Cyclic AMP / Q000378:metabolism*; D017362:Cyclic AMP Response Element-Binding Protein; D004268:DNA-Binding Proteins; D015967:Gene Expression Regulation, Viral; D009687:Nuclear Proteins / Q000378:metabolism; D009858:Oncogenic Viruses / Q000235:genetics / Q000254:growth & development; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D020218:Response Elements; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*; D015533:Transcriptional Activation
D051697:Activating Transcription Factor 1; D017500:Adenovirus E1A Proteins; D017502:Adenovirus E2 Proteins; C115163:CREB1 protein, human; D017362:Cyclic AMP Response Element-Binding Protein; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D000242:Cyclic AMP; D050882:CREB-Binding Protein