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  • Oral presentation
  • Open Access

Sequence-Specific Vpr Binding to HIV-1 LTR C/EBP Binding Sites and Adjacent Regions

  • 1,
  • 1,
  • 1 and
  • 1
Retrovirology20052 (Suppl 1) :S156

  • Published:


  • Human Immunodeficiency Virus
  • Long Terminal Repeat
  • Electrophoretic Mobility Shift Assay
  • Mobility Shift
  • Competitive Interaction

Human immunodeficiency virus type 1 (HIV-1) Vpr is a virion-associated protein that transactivates the HIV-1 long terminal repeat (LTR), as well as other eukaryotic promoters. Here we used the electrophoretic mobility shift assay to demonstrate the direct binding of purified Vpr (strain pNL4-3) to HIV-1 LTR sequences that span the adjacent C/EBP site I, NF-kB site II, and ATF/CREB binding site. Binding between HIV-1 Vpr and the LTR C/EBP site II was also observed. A total of 94.7% of LTRs derived from peripheral blood displayed high relative Vpr binding affinity with respect to C/EBP site I, while only 5.3% exhibited a low relative Vpr binding affinity. Virtually all LTRs derived from peripheral blood exhibited a high relative Vpr binding phenotype relative to C/EBP site II. Additional studies have 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. Studies have also suggested a competitive interaction between C/EBP factors and Vpr for this region of the LTR. These studies suggest that Vpr may regulate the interaction of members of the C/EBP transcription factor family with the viral LTR.


Authors’ Affiliations

Department of Microbiology and Immunology and Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA


© The Author(s) 2005