title: Role of enhancin in Mamestra configurata nucleopolyhedrovirus virulence: selective degradation of host peritrophic matrix proteins.
abstract: To infect per os, baculovirus virions cross the peritrophic matrix (PM) to reach the midgut epithelium. Insect intestinal mucins (IIMs) are PM proteins that protect the PM and aid passage of the food bolus through the gut. Some baculoviruses, including Mamestra configurata nucleopolyhedrovirus (MacoNPV-A), encode metalloproteases, known as enhancins, that facilitate infection by degrading IIMs. We examined the interaction between MacoNPV-A enhancin and M. configurata IIMs both in vivo and in vitro. Per os inoculation of M. configurata larvae with MacoNPV-A occlusion bodies (OBs) resulted in the degradation of McIIM4 within 4 h of OB ingestion, while McIIM2 was unaffected. The PM recovered by 8 h post-inoculation. To investigate whether enhancin was responsible for the degradation of IIM, a recombinant Autographa californica multiple nucleopolyhedrovirus expressing MacoNPV enhancin (AcMNPV-enMP2) was constructed. Enhancin was found to be a component of occlusion-derived virions in AcMNPV-enMP2 and MacoNPV-A. In in vitro assays, McIIM4 was degraded after MacoNPV-A and AcMNPV-enMP2 treatments. Degradation of McIIM4 was inhibited by EDTA, a metalloprotease inhibitor, indicating that the degradation was due to enhancin activity. Thus, MacoNPV-A enhancin is able to degrade major structural PM proteins, but exhibits target substrate specificity.
authors.affiliation: Department of Plant Protection, College of Agriculture, University of Ankara, Ankara, Turkey.|Department of Biology, University of Saskatchewan, Saskatoon, SK, Canada.|Agriculture and Agri-Food Canada, Saskatoon, SK, Canada.
authors.forename: Umut
authors.initials: U
authors.lastname: Toprak
authors.affiliation: Agriculture and Agri-Food Canada, Saskatoon, SK, Canada.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Harris
authors.affiliation: Agriculture and Agri-Food Canada, Saskatoon, SK, Canada.
authors.forename: Douglas
authors.initials: D
authors.lastname: Baldwin
authors.affiliation: Agriculture and Agri-Food Canada, Summerland, BC, Canada.
authors.forename: David
authors.initials: D
authors.lastname: Theilmann
authors.affiliation: Department of Biology, University of Saskatchewan, Saskatoon, SK, Canada.
authors.forename: Cedric
authors.initials: C
authors.lastname: Gillott
authors.affiliation: Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, SK, Canada.|Agriculture and Agri-Food Canada, Saskatoon, SK, Canada.
authors.forename: Dwayne D
authors.initials: DD
authors.lastname: Hegedus
authors.affiliation: Department of Biology, University of Saskatchewan, Saskatoon, SK, Canada.|Agriculture and Agri-Food Canada, Saskatoon, SK, Canada.
authors.forename: Martin A
authors.initials: MA
authors.lastname: Erlandson
mesh_terms: D000818:Animals; D015153:Blotting, Western; D004064:Digestive System / Q000821:virology; D005752:Gastric Mucins / Q000378:metabolism*; D007814:Larva / Q000821:virology; D007915:Lepidoptera / Q000821:virology; D045726:Metalloproteases / Q000235:genetics / Q000502:physiology*; D017924:Nucleopolyhedroviruses / Q000235:genetics / Q000472:pathogenicity*; D010802:Phylogeny; D014764:Viral Proteins / Q000235:genetics / Q000502:physiology*; D014774:Virulence
chemical_list: D005752:Gastric Mucins; D014764:Viral Proteins; D045726:Metalloproteases