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Foamy virus envelope glycoprotein-mediated entry involves a pH-dependent fusion process.

Marcus Picard-Maureau·Gergely Jarmy·Angelika Berg·Axel Rethwilm·Dirk Lindemann
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Abstract

In general, enveloped viruses use two different entry strategies and are classified accordingly into pH-dependent and pH-independent viruses. Different members of the retrovirus family use one or the other strategy. Little is known about the uptake of foamy viruses (FV), a special group of retroviruses, into the target cells. In this study, we examined the pH dependence of FV entry by analyzing FV envelope glycoprotein (Env)-mediated infection of target cells with murine leukemia virus or FV vector pseudotypes in the presence of various lysosomotropic agents. Similar to vesicular stomatitis virus glycoprotein G (VSV-G)-mediated uptake, FV Env-mediated entry was inhibited by various lysosomotropic agents, suggesting a pH-dependent endocytic pathway. However, in contrast to its effect on VSV-G pseudotypes, chloroquine failed to reduce the infectivity of FV Env pseudotypes, implying that the pathway is different from that of VSV-G. Glycoproteins of various other FV species showed inhibition profiles similar to that of the prototype FV (PFV) Env. Analysis of the pH dependence of the FV Env-mediated fusion process in a cell-to-cell fusion assay revealed an induction of syncytium formation by a short exposure to acidic pH, peaking around pH 5.5. Interestingly, of all FV Env species analyzed, only the PFV Env had a significant fusion activity at neutral pH. Taken together, these data suggest a pH-dependent endocytic pathway for infection of target cells by FV.

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Ammonium ChlorideAnimalsAnti-Bacterial AgentsCell FusionCell LineGenetic VectorsGiant CellsGreen Fluorescent ProteinsHumansHydrogen-Ion ConcentrationLeukemia Virus, MurineLuminescent ProteinsMacrolidesMembrane FusionNigericinSpumavirusTransduction, GeneticViral Envelope ProteinsJournal ArticleResearch Support, Non-U.S. Gov't

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Marcus Picard-Maureau, Gergely Jarmy, Angelika Berg, Axel Rethwilm, Dirk Lindemann. 2003. Foamy virus envelope glycoprotein-mediated entry involves a pH-dependent fusion process.. https://doi.org/10.1128/jvi.77.8.4722-4730.2003

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