Identification of Residues outside of the Receptor Binding Domain That Influence the Infectivity and Tropism of Porcine Endogenous Retrovirus
- 1 August 2008
- journal article
- Published by American Society for Microbiology in Journal of Virology
- Vol. 82 (15), 7483-7491
- https://doi.org/10.1128/jvi.00295-08
Abstract
Identification of determinants of human tropism of porcine endogenous retrovirus (PERV) is critical to understanding the risk of transmission of PERV to recipients of porcine xenotransplantation products. Previously, we showed that a chimeric envelope cDNA encoding the 360 N-terminal residues of the human-tropic PERV envelope class A (PERV-A) SU and the 130 C-terminal residues of the pig-tropic PERV-C SU and all of TM (PERV-A/C) showed a 100-fold decrease in infectivity titer on human cells (M. Gemeniano, O. Mpanju, D. R. Salomon, M. V. Eiden, and C. A. Wilson, Virology 346:108-117, 2006). To identify residues important for human cell infection, we performed site-directed mutagenesis on each of the nine residues, singly or in combination, that distinguish the C-terminal region of PERV-C from PERV-A. Of the nine amino acids, two single-amino-acid substitutions, Q374R and I412V, restored the infectivity of human cells to the chimeric PERV-A/C to a titer equivalent to that of PERV-A. In contrast, PERV-A/C mutant envelope Q439P resulted in undetectable infection of human cells and an approximately 1,000-fold decrease in control pig cells. Mutation of K441R rescued mutants that carried Q439P, suggesting an incompatibility between the proline residue at this position and the presence of KK in the proteolytic cleavage signal. We confirmed this incompatibility with vectors carrying PERV-A envelope mutant R462K that were also rendered noninfectious. Finally, tropism of vectors carrying PERV-C envelope mutants with only four amino acid changes in the C terminus of PERV-C envelope, NHRQ436YNRP plus K441R, was shifted to one similar to that of PERV-A. Our results show an important and previously unrecognized role for infectivity and tropism for residues at the C terminus of SU.This publication has 43 references indexed in Scilit:
- Transient transmission of porcine endogenous retrovirus to fetal lambs after pig islet tissue xenotransplantationImmunology & Cell Biology, 2007
- Isolation and Characterization of an Infectious Replication-Competent Molecular Clone of Ecotropic Porcine Endogenous Retrovirus Class CJournal of Virology, 2006
- Pig islet xenotransplantation: activation of porcine endogenous retrovirus in the immediate post-transplantation periodXenotransplantation, 2005
- Involvement of the C-Terminal Disulfide-Bonded Loop of Murine Leukemia Virus SU Protein in a Postbinding Step Critical for Viral EntryJournal of Virology, 2005
- Porcine Endogenous Retrovirus Transmission Characteristics of an Inbred Herd of Miniature SwineJournal of Virology, 2002
- Specificity in Receptor Usage by T-Cell-Tropic Feline Leukemia Viruses: Implications for the In Vivo Tropism of Immunodeficiency-Inducing VariantsJournal of Virology, 2001
- Receptors and Entry Cofactors for Retroviruses Include Single and Multiple Transmembrane-Spanning Proteins as well as Newly Described Glycophosphatidylinositol-Anchored and Secreted ProteinsMicrobiology and Molecular Biology Reviews, 2001
- Comparison of Replication-Competent Molecular Clones of Porcine Endogenous Retrovirus Class A and Class B Derived from Pig and Human CellsJournal of Virology, 2001
- Detection and Characterization of Porcine Endogenous Retrovirus in Porcine Plasma and Porcine Factor VIIIJournal of Virology, 2001
- Activation of Membrane Fusion by Murine Leukemia Viruses Is Controlled in cis or in trans by Interactions between the Receptor-Binding Domain and a Conserved Disulfide Loop of the Carboxy Terminus of the Surface GlycoproteinJournal of Virology, 2001