title: HIV-1 Vpr binding to HIV-1 LTR C/EBP cis-acting elements and adjacent regions is sequence-specific.
abstract: Human immunodeficiency virus type 1 (HIV-1) viral protein R (Vpr) is a 14 kDa virion-associated protein that transactivates the HIV-1 long terminal repeat (LTR) as well as other eukaryotic promoters. Vpr also functions in nuclear localization and import of the HIV-1 preintegration complex (PIC), cell cycle arrest at the G(2)/M interface, and virion packaging. Electrophoretic mobility shift analysis has been utilized to demonstrate a direct association between purified Vpr (strain pNL4-3) and HIV-1 LTR sequences that span the adjacent C/EBP site I, NF-kappaB site II, and ATF/CREB binding site (nt -95 to -130, relative to the start of transcription). A similar interaction has been observed between HIV-1 Vpr and LTR C/EBP site II (nt -167 to -175). A total of 94.7% of LTRs derived from peripheral blood contained C/EBP site I variants that displayed a high relative Vpr binding affinity phenotype, while only 5.3% exhibited a low relative Vpr binding affinity phenotype. All LTRs derived from peripheral blood exhibited a high relative Vpr binding phenotype at C/EBP site II. These results suggest a preference for the maintenance of two cis-acting elements with high affinity for Vpr within LTRs derived from peripheral blood. Additional studies have also demonstrated that naturally occurring sequence variation within C/EBP site I and II can dramatically alter the relative affinity of Vpr for these cis-acting elements. These studies suggest that Vpr may regulate the interaction of members of the C/EBP transcription factor family with the viral LTR.
authors.affiliation: Department of Microbiology and Immunology, The Pennsylvania State University, College of Medicine, (H107), 500 University Drive, P.O. Box 850, Hershey, PA 17033, USA.
authors.forename: Tricia H
authors.initials: TH
authors.lastname: Hogan
authors.forename: Michael R
authors.initials: MR
authors.lastname: Nonnemacher
authors.forename: Fred C
authors.initials: FC
authors.lastname: Krebs
authors.forename: Andrew
authors.initials: A
authors.lastname: Henderson
authors.forename: Brian
authors.initials: B
authors.lastname: Wigdahl
mesh_terms: D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D022762:CCAAT-Enhancer-Binding Proteins / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay / Q000379:methods; D016336:Gene Products, vpr / Q000235:genetics / Q000378:metabolism*; D016325:HIV Long Terminal Repeat / Q000235:genetics*; D015497:HIV-1 / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D009841:Oligonucleotides / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D012689:Sequence Homology, Nucleic Acid; D020298:U937 Cells; D054325:vpr Gene Products, Human Immunodeficiency Virus
chemical_list: D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D016336:Gene Products, vpr; D009841:Oligonucleotides; D054325:vpr Gene Products, Human Immunodeficiency Virus