Involvement of transcription factor YB-1 in human T-cell lymphotropic virus type I basal gene expression.
Sequences which control basal human T-cell lymphotropic virus type I (HTLV-I) transcription likely play an important role in initiation and maintenance of virus replication. We previously identified and analyzed a 45-nucleotide sequence (downstream regulatory element 1 [DRE 1]), +195 to +240, at the boundary of the R/U5 region of the long terminal repeat which is required for HTLV-I basal transcription. We identified a protein, p37, which specifically bound to DRE 1. An affinity column fraction, containing p37, stimulated HTLV-I transcription approximately 12-fold in vitro. We now report the identification of a cDNA clone (15B-7), from a Jurkat expression library, that binds specifically to the DRE 1 regulatory sequence. Binding of the cDNA fusion protein, similarly to the results obtained with purified Jurkat protein, was decreased by introduction of site-specific mutations in the DRE 1 regulatory sequence. In vitro transcription and translation of 15B-7 cDNA produced a fusion protein which bound specifically to the HTLV-I +195 to +240 oligonucleotide. The partial cDNA encodes a protein which is homologous to the C-terminal 196 amino acids of the 36-kDa transcription factor, YB-1. Cotransfection of a YB-1 expression plasmid increases HTLV-I basal transcription approximately 14-fold in Jurkat T lymphocytes. On the basis of the molecular weight, DNA-binding characteristics, and in vivo transactivation activity, we suggest that the previously identified DRE 1-binding protein, p37, is YB-1.
Kashanchi
F
F
Laboratory of Molecular Virology, National Institutes of Health, Bethesda, Maryland 20892.
Duvall
J F
JF
Dittmer
J
J
Mireskandari
A
A
Reid
R L
RL
Gitlin
S D
SD
Brady
J N
JN
D000595:Amino Acid Sequence; D001483:Base Sequence; D022762:CCAAT-Enhancer-Binding Proteins; D002460:Cell Line; D002472:Cell Transformation, Viral; D015500:Chloramphenicol O-Acetyltransferase / Q000096:biosynthesis; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics*; D015967:Gene Expression Regulation, Viral; D015368:Human T-lymphotropic virus 1 / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D051839:NFI Transcription Factors; D009687:Nuclear Proteins; D012333:RNA, Messenger / Q000032:analysis; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D012045:Regulatory Sequences, Nucleic Acid; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013601:T-Lymphocytes; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics*; D051840:Y-Box-Binding Protein 1
D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D051839:NFI Transcription Factors; D009687:Nuclear Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D051840:Y-Box-Binding Protein 1; C070856:YBX1 protein, human; D015500:Chloramphenicol O-Acetyltransferase