Distinct DNA targets for trans-activation by HTLV-1 tax and adenovirus E1A.
The HTLV-1 LTR is trans-activated by both the HTLV-1 tax (p40x) and adenovirus E1A gene products. Previous experiments have localized tax-responsive cis-elements to three 21-bp repeat units within the promoter, as well as a fourth region located between the middle and proximal repeats. A sequence TGACG, resembling the ATF/CREB recognition element, is located at the center of each of these repeat units. Mutation of this ATF/CREB site in the 21-bp repeats impairs both tax and E1A-dependent trans-activation. However, assays of a variety of promoter mutants demonstrate that sequences required for E1A and tax induction differ, suggesting that these two viral trans-activators target different factors. In addition, although the adenovirus E4 promoter also contains three ATF/CREB sites involved in E1A activation, tax does not activate this promoter. Finally, we also find that the TATAA element of the HTLV-1 LTR contributes to E1A-dependent activation but not tax activation. We concluded that although both trans-activators exhibit similarities in their activation properties, the targets for activation must differ.
Nicholas
J
J
Howard Hughes Medical Institute, Department of Microbiology and Immunology, Duke University Medical Center, Durham, North Carolina 27710.
Nevins
J R
JR
D017456:Adenovirus Early Proteins; D000260:Adenoviruses, Human / Q000235:genetics*; D001483:Base Sequence; D001665:Binding Sites; D015967:Gene Expression Regulation, Viral; D016356:Gene Products, tax / Q000502:physiology*; D005814:Genes, Viral; D006367:HeLa Cells; D015368:Human T-lymphotropic virus 1 / Q000235:genetics*; D006801:Humans; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D009856:Oncogene Proteins, Viral / Q000502:physiology*; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics*; D014157:Transcription Factors / Q000502:physiology; D015678:Viral Structural Proteins / Q000235:genetics
D017456:Adenovirus Early Proteins; D016356:Gene Products, tax; D009856:Oncogene Proteins, Viral; D014157:Transcription Factors; D015678:Viral Structural Proteins