Protein-DNA interactions within DNase I-hypersensitive sites located downstream of the HIV-1 promoter.
We have examined by in vitro footprinting a region located downstream of the human immunodeficiency virus, type 1 (HIV-1) promoter found to be hypersensitive to DNase I digestion in vivo. Recognition sites for several constitutive or inducible DNA binding factors were identified. Three AP-1 binding sites and an AP-3-like motif were situated within the R-U5 region of the long terminal repeat. A novel purine-rich motif (5'-GAAAGC-GAAAGDD-3' (D represents G, A, or T residues)), which interacts with a nuclear factor designated downstream binding factor 1 (DBF1), and two juxtaposed Sp-1 binding sites were located in the untranslated sequence immediately downstream of the 5'-long terminal repeat. Genomic footprinting of these sequence elements in the HIV-1 chronically infected cell lines revealed that the DBF1 and Sp-1 sites are occupied in vivo. Furthermore, transient transfection assays showed that point mutations in the DBF1 binding site decreased significantly the HIV-1 basal promoter activity. Taken together, these results suggest that the DBF1 play a role in the HIV-1 transcription regulation.
el Kharroubi
A
A
Laboratory of Viral and Molecular Pathogenesis, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892.
Verdin
E
E
D001483:Base Sequence; D002478:Cells, Cultured; D004279:DNA, Viral / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D003850:Deoxyribonuclease I; D015497:HIV-1 / Q000235:genetics*; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D014176:Protein Biosynthesis
D004279:DNA, Viral; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D003850:Deoxyribonuclease I