Conserved Amino Acids of the Human Immunodeficiency Virus Type 2 Vpx Nuclear Localization Signal Are Critical for Nuclear Targeting of the Viral Preintegration Complex in Non-Dividing Cells

Authors

Michael Belshan, Creighton UniversityFollow
Lisa A. Mahnke, Washington University School of Medicine
Lee Ratner, Washington University School of Medicine

Document Type

Article

Date of this Version

March 2006

Comments

Published in Virology 346:1 (March 1, 2006), pp. 118–126; doi 10.1016/j.virol.2005.10.036 Copyright © 2005 Elsevier Inc. Used by permission. http://www.sciencedirect.com/science/journal/00426822

Abstract

The HIV-2 viral accessory protein Vpx is related to, but distinct from the Vpr protein of HIV-1. Vpx is packaged into virions and as a component of the viral preintegration complex (PIC) is required for efficient virus replication in non-dividing cells. We have previously reported that the minimal transferable region of Vpx that contained karyophilic properties was aa 65 to 72. Analysis of Vpx sequences from various HIV-2/SIV strains reveals that this region contains highly conserved amino acids, including two basic residues (K68, R70) and three tyrosines (Y66, Y69, Y71). Here, we demonstrate that mutation of the basic or tyrosine residues abolishes PIC nuclear import in arrested cells as assessed by PCR detection of viral integration. Examination of cell-free virus by Western blot indicated that all mutant proteins were incorporated into virions, suggesting that the lack of replication in arrested cells was not due to a loss of Vpx in target cells. Together, these studies map critical residues of the Vpx nuclear localization signal that are required for efficient infection of non-dividing cells.