A unique enhancer element for the trans activator (p40tax) of human T-cell leukemia virus type I that is distinct from cyclic AMP- and 12-O-tetradecanoylphorbol-13-acetate-responsive elements.
The trans activator (p40tax) of human T-cell leukemia virus type I (HTLV-I) is a transcriptional factor that activates the long terminal repeat (LTR) of HTLV-I and interleukin-2 receptor alpha. We examined the HTLV-I enhancer responsible for tax-mediated trans activation and identified (A/T)(G/C)(G/C)CNNTGACG(T/A) as a plausible tax-responsive element (TRE). The putative TRE in the LTR was found to be different from the elements required for activation by cycle AMP and 12-O-tetradecanoylphorbol-13-acetate, although these elements overlapped each other. The TRE was also different from a binding site of an NF-kappa B-like factor that was identified in the interleukin-2 receptor alpha promoter and human immunodeficiency virus LTR as a TRE. The latter result was further demonstrated by the failure of the NF-kappa B sequence to compete with the TRE of the LTR in a protein-binding assay. These findings indicate that tax function and its cascade can modulate activities of various enhancer sequences, which are probably regulated by distinct DNA-binding factors.
Fujisawa
J
J
Department of Viral Oncology, Cancer Institute, Tokyo, Japan.
Toita
M
M
Yoshida
M
M
D001483:Base Sequence; D002460:Cell Line; D000242:Cyclic AMP / Q000378:metabolism*; D004742:Enhancer Elements, Genetic; D005786:Gene Expression Regulation; D015486:HTLV-I Antigens / Q000235:genetics*; D015368:Human T-lymphotropic virus 1 / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D010957:Plasmids; D011485:Protein Binding; D012091:Repetitive Sequences, Nucleic Acid; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D015534:Trans-Activators; D014157:Transcription Factors / Q000235:genetics*; D014162:Transfection
D015486:HTLV-I Antigens; D015534:Trans-Activators; D014157:Transcription Factors; D000242:Cyclic AMP; D013755:Tetradecanoylphorbol Acetate