title: Characterization of interactions between transcription factors and a regulatory region spanning nt -320 to -281 of the HIV-1 LTR in T-lymphoid and non-T-lymphoid cells.
abstract: HIV-1 gene expression is regulated by the interplay of transcription factors with multiple binding motifs present within the U3, R and U5 regions of the long terminal repeat (LTR). Here we report novel DNA binding complexes (termed 9a, 9b and 9c) between nuclear proteins from T-lymphoid and non-T-lymphoid cells and a region of the U3 LTR between nucleotides (nts) -320 to -281 in the HIV strain HXB2. Complex 9b bound a motif predicted to bind E-box or c-Myb proteins and a partially overlapping dyad symmetrical motif, and included basic helix-loop-helix proteins (E12, E47 or ITF-1) but surprisingly not c-Myb. Complex 9c, which bound to a pair of GATA sites, included GATA-3 and GATA-4 in Jurkat and MT-2 cells, respectively. We also demonstrate that the c-Myb/E-box and GATA sites form a bipartite motif required for the formation of complex 9a. Transient transfection experiments with T cells revealed that in the context of a minichromosome assembled full-length LTR, mutation of region -320 to -281 increased basal and PMA-stimulated LTR activity. These findings suggest that this region is an important component of the HIV-1 LTR required for response to different cellular transcription factors.
authors.affiliation: Laboratory for Physiological Chemistry and Centre for Biomedical Genetics, University Medical Centre, Utrecht, The Netherlands.
authors.forename: Lloyd A
authors.initials: LA
authors.lastname: Pereira
authors.forename: Melissa J
authors.initials: MJ
authors.lastname: Churchill
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Elefanty
authors.forename: Theo
authors.initials: T
authors.lastname: Gouskos
authors.forename: Paul F
authors.initials: PF
authors.lastname: Lambert
authors.forename: Robert G
authors.initials: RG
authors.lastname: Ramsay
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Deacon
mesh_terms: D001665:Binding Sites; D004268:DNA-Binding Proteins / Q000378:metabolism / Q000494:pharmacology; D005809:Genes, Regulator / Q000187:drug effects / Q000235:genetics*; D016325:HIV Long Terminal Repeat / Q000187:drug effects / Q000235:genetics*; D015497:HIV-1 / Q000235:genetics; D006801:Humans; D009687:Nuclear Proteins / Q000378:metabolism / Q000494:pharmacology; D011485:Protein Binding; D020598:Proto-Oncogene Proteins c-myb / Q000378:metabolism; D013601:T-Lymphocytes / Q000378:metabolism / Q000821:virology*; D014157:Transcription Factors / Q000378:metabolism* / Q000494:pharmacology; D014158:Transcription, Genetic / Q000187:drug effects; D014407:Tumor Cells, Cultured
chemical_list: D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D020598:Proto-Oncogene Proteins c-myb; D014157:Transcription Factors