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E4F and ATF, two transcription factors that recognize the same site, can be distinguished both physically and
R J Rooney1, P Raychaudhuri, J R Nevins
1Department of Microbiology and Immunology, Howard Hughes Medical Institute, Duke University Medical Center, Durham, North Carolina 27710.
Molecular and Cellular Biology
|October 1, 1990
Summary
A novel transcription factor, E4F, is crucial for adenovirus E4 promoter activation by E1A. E4F levels increase upon infection, unlike ATF, and its specific DNA binding correlates with promoter inducibility.
Area of Science:
- Molecular Biology
- Virology
- Gene Regulation
Background:
- Adenovirus E4 promoter contains an element critical for E1A-dependent trans activation.
- This element is recognized by multiple nuclear factors, including ATF and E4F.
Purpose of the Study:
- To investigate the role of ATF and E4F in adenovirus E4 promoter regulation.
- To determine the specific DNA-binding properties and functional significance of E4F in E1A-mediated trans activation.
Main Methods:
- DNA-binding assays to measure ATF and E4F levels and binding specificity.
- Cotransfection assays with modified expression vectors to assess promoter inducibility.
- Analysis of DNA-protein complex stability.
Main Results:
- E4F levels increase significantly upon adenovirus infection, while ATF levels remain unchanged.
- E4F exhibits distinct DNA sequence recognition compared to ATF, binding only a subset of ATF sites.
- Sequences binding E4F confer E1A inducibility, whereas ATF-binding sequences do not.
- E4F forms a stable complex with the E4 promoter, unlike the unstable ATF complex.
Conclusions:
- E4F, not ATF, is the primary factor mediating E1A-dependent trans activation of the adenovirus E4 promoter.
- The specific DNA-binding properties and infection-induced increase in E4F activity are key to E4 promoter stimulation.