title: Characterization of a leucine-zipper-like domain in Vpr protein of human immunodeficiency virus type 1.
abstract: Human immunodeficiency virus type 1 (HIV-1) replicates productively in vitro in CD4(+)-T cells and/or macrophages. In the host, however, HIV-1 replication may be restricted by the quiescence of susceptible cells. Vpr is a 15-kDa late viral gene product, which is assembled in the virion and suspected to enhance HIV-1 replication in the infected host. We demonstrated previously that Vpr interacted specifically with the cellular transcription factor Sp1, and activated transcription from the HIV-1 long-terminal-repeat. Both Vpr-Sp1 interaction and trans-activation by Vpr required a central Leu/Ile-rich domain (LR domain, aa 60-81) in Vpr. This domain of Vpr was also found critical for Vpr interaction with another cellular protein of 180 kDa. We now provide biochemical evidence that the Vpr LR-domain has a leucine-zipper-like structure. The leucine-zipper structure has been found in a variety of cellular transcription factors, which use the leucine-zipper domain to form a specific dimer before they can bind to DNA through an upstream basic domain. The LR domain of HIV-1 Vpr, when fused to the basic domain of the cellular transcription factor CREB, was capable of supporting specific DNA binding by the CREB basic domain. Point mutational analysis of the Leu/Ile residues in the LR domain suggested that multiple Leu/Ile residues may be involved in maintaining the leucine-zipper-like structure. Mutagenesis in the context of the full-length Vpr also helped identify Leu/Ile residues may be involved in maintaining the leucine-zipper-like structure. Mutagenesis in the context of the full-length Vpr also helped identify Leu/Ile residues critical for Vpr interaction with the cellular 180-kDa protein. These results suggested that the leucine-zipper-like domain may be an important functional determinant for HIV-1 Vpr.
authors.affiliation: Marion Merrell Dow Foundation, Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City 66160-7424, USA.
authors.forename: L
authors.initials: L
authors.lastname: Wang
authors.forename: S
authors.initials: S
authors.lastname: Mukherjee
authors.forename: O
authors.initials: O
authors.lastname: Narayan
authors.forename: L J
authors.initials: LJ
authors.lastname: Zhao
mesh_terms: D000595:Amino Acid Sequence; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D016336:Gene Products, vpr / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D015497:HIV-1 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D016350:Leucine Zippers; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D017354:Point Mutation; D011485:Protein Binding; D011487:Protein Conformation; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D054325:vpr Gene Products, Human Immunodeficiency Virus
chemical_list: D017362:Cyclic AMP Response Element-Binding Protein; D016336:Gene Products, vpr; D011993:Recombinant Fusion Proteins; D054325:vpr Gene Products, Human Immunodeficiency Virus; D004247:DNA