c-fos promoter trans-activation by the tax1 protein of human T-cell leukemia virus type I.
To understand the mechanisms of oncogenesis by human T-cell leukemia virus type I, we have investigated the ability of the tax1, protein to modulate transcription of protooncogenes. By using a transient cotransfection assay, we report that the protooncogene fos promoter is transactivated by tax1 in a variety of cell types. Two regions containing upstream sequences between positions -362/-324 and -323/-276 of the c-fos promoter responded to this activation and also conferred tax1 responsiveness to the heterologous herpesvirus thymidine kinase promoter. These two sequences include elements mediating the induction by v-sis-conditioned medium and serum, phorbol ester, or epidermal growth factor, respectively. Furthermore, expression of the endogenous c-fos gene was activated by tax1 in human T-cell leukemia virus type I-infected cell lines. In contrast, no trans-activation of the c-myc or c-Ha-ras promoter was observed.
Fujii
M
M
Molecular Biology and Virology Laboratory, Salk Institute, San Diego, CA 92138.
Sassone-Corsi
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P
Verma
I M
IM
D006528:Carcinoma, Hepatocellular; D002460:Cell Line; D005786:Gene Expression Regulation; D015486:HTLV-I Antigens / Q000378:metabolism*; D006367:HeLa Cells / Q000378:metabolism; D015368:Human T-lymphotropic virus 1 / Q000235:genetics*; D006801:Humans; D008113:Liver Neoplasms; D010957:Plasmids; D011401:Promoter Regions, Genetic; D011519:Proto-Oncogenes; D015534:Trans-Activators; D014157:Transcription Factors / Q000378:metabolism*; D014162:Transfection
D015486:HTLV-I Antigens; D015534:Trans-Activators; D014157:Transcription Factors