Exposure of ichnovirus particles to digitonin leads to enhanced infectivity and induces fusion from without in an in vitro model system.
Unlike most viruses, the mature ichnovirus particle possesses two unit membrane envelopes. Following loss of the outer membrane in vivo, nucleocapsids are believed to gain entry into the cytosol via a membrane fusion event involving the inner membrane and the plasma membrane of susceptible host cells; accordingly, experimentally induced damage to the outer membrane might be expected to increase infectivity. Here, in an attempt to develop an in vitro model system for studying ichnovirus infection, we show that digitonin-induced disruption of the virion outer membrane not only increases infectivity, but also uncovers an activity not previously associated with any polydnavirus: fusion from without.
Stoltz
Don
D
Department of Microbiology and Immunology, Dalhousie University, Halifax, NS B3H 4H7, Canada.
Lapointe
Renée
R
Laurentian Forestry Centre, Canadian Forest Service, Natural Resources Canada, Quebec City, QC G1V 4C7, Canada.
Makkay
Andrea
A
Department of Microbiology and Immunology, Dalhousie University, Halifax, NS B3H 4H7, Canada.
Cusson
Michel
M
Laurentian Forestry Centre, Canadian Forest Service, Natural Resources Canada, Quebec City, QC G1V 4C7, Canada.
D000818:Animals; D002460:Cell Line; D004072:Digitonin / Q000494:pharmacology*; D018071:Polydnaviridae / Q000187:drug effects* / Q000472:pathogenicity* / Q000502:physiology; D018411:Spodoptera; D014771:Virion / Q000187:drug effects* / Q000472:pathogenicity*; D053586:Virus Internalization / Q000187:drug effects*; D014780:Viruses
D004072:Digitonin