A new regulatory element that augments the Tax-dependent enhancer of human T-cell leukemia virus type 1 and cloning of cDNAs encoding its binding proteins.
The Tax protein of human T-cell leukemia virus type 1 (HTLV-1) trans activates the 21-bp enhancer of HTLV-1. A sequence of more than two copies of the 21-bp enhancer is efficiently activated by Tax, but one copy is not activated extensively. Another sequence (TRE-2, positions -163 to -117) adjacent to the 21-bp enhancer in the long terminal repeat of HTLV-1 can enhance a single copy of the 21-bp enhancer activity in trans activation by Tax. This sequence contains motifs related to the Ets- and NF-kappa B-binding sequences, but mutations at these sites indicated that neither is responsive to cooperation with the 21-bp enhancer. A deletion mutation of TRE-2 identified 25 bases at positions -158 to -134 (TRE-2S) as an essential sequence, and TRE-2S was sufficient to give maximum cooperation with one copy of the 21-bp enhancer in trans activation by Tax protein. Using TRE-2S as a probe, we screened a cDNA library of HUT102 cells by the Southwestern (DNA-protein) procedure and isolated two cDNA clones, THP-1 and -2. These two clones encode TRE-2S-binding proteins, and they differ by only an extra 17 amino acids in THP-2. Both THP proteins contain five zinc finger motifs which are strikingly similar to those of the GLI family, an amplified gene product in glyoma cells. The binding site of THP-1 and -2 was GAACCACCCA in TRE-2S, which is highly homologous to the GLI-binding site. These results suggest that binding of THP to TRE-2S may be involved in cooperation with one copy of the 21-bp enhancer in responding to Tax trans activation.
Tanimura
A
A
Department of Cellular and Molecular Biology, University of Tokyo, Japan.
Teshima
H
H
Fujisawa
J
J
Yoshida
M
M
D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D004279:DNA, Viral / Q000235:genetics; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D016356:Gene Products, tax / Q000378:metabolism*; D015368:Human T-lymphotropic virus 1 / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D051741:Kruppel-Like Transcription Factors; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D009838:Oligodeoxyribonucleotides; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D050783:Proto-Oncogene Proteins c-ets; D011994:Recombinant Proteins / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors; D014162:Transfection; D014407:Tumor Cells, Cultured; D014764:Viral Proteins; D000075746:Zinc Finger Protein Gli2; D016335:Zinc Fingers / Q000235:genetics
D004279:DNA, Viral; D004268:DNA-Binding Proteins; C082593:GLI2 protein, human; D016356:Gene Products, tax; D051741:Kruppel-Like Transcription Factors; D009687:Nuclear Proteins; D009838:Oligodeoxyribonucleotides; D011518:Proto-Oncogene Proteins; D050783:Proto-Oncogene Proteins c-ets; D011994:Recombinant Proteins; D014157:Transcription Factors; D014764:Viral Proteins; D000075746:Zinc Finger Protein Gli2; D015500:Chloramphenicol O-Acetyltransferase