Human immunodeficiency virus type 1 (HIV-1) Vpr, a 14-kDa virion-associated protein, plays an important role in the viral life cycle. Using a panel of truncated HIV-1 LTR-CAT constructs and Vpr expression plasmid, we have identified sequences from nucleotide -278 to -176 in LTR as Vpr-mediated transactivation domain. This region includes the giucocorticoid response element (GRE) in HIV-1 LTR. Transactivation by Vpr was noted with the HIV-1 LTR reporter constructs containing CAT or luciferase. A similar effect was also observed with a construct in which the GRE motif was linked to CAT. Studies involving Vpr mutants identified that helical domains I and III, and amino acid residues at G75 and C76, are responsible for GRE-mediated LTR transactivation. The transactivation function of Vpr is independent of its cell cycle arrest activity. Further, viral replication studies indicated that Vpr-mediated increase in viral replication is directly correlated with the ability of Vpr to transactivate HIV-1 LTR. The results presented here demonstrate that Vpr activates HIV-1 LTR through the host GR pathway and suggest that an intact GRE in the LTR is critical for Vpr activity. © 2001 Academic Press.
CITATION STYLE
Vanitharani, R., Mahalingam, S., Rafaeli, Y., Singh, S. P., Srinivasan, A., Weiner, D. B., & Ayyavoo, V. (2001). HIV-1 Vpr transactivates LTR-directed expression through sequences present within -278 to -176 and increases virus replication in vitro. Virology, 289(2), 334–342. https://doi.org/10.1006/viro.2001.1153
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