A serpin from the parasitoid wasp Leptopilina boulardi targets the Drosophila phenoloxidase cascade.
The insect phenoloxidase (PO) cascade is known to be tightly regulated by serine proteases and serine protease inhibitors of the serpin family. As a key component of the insect immune system, it is also suspected to be inhibited by several endoparasitoid wasps, insects that develop inside other arthropods as hosts. However, the underlying mechanisms of this inhibition are largely undescribed. Here, we report the characterization of a gene encoding a serpin, LbSPNy, highly expressed in the venom of the wasp Leptopilina boulardi (IS(y) type), and we show that either the venom or the recombinant LbSPNy inhibit the PO cascade in the hemolymph of Drosophila yakuba host larva. Altogether, our results identify the first serpin used as a virulence factor by a parasitoid wasp and show that it disrupts the activation pathway of the PO in the Drosophila host.
Colinet
Dominique
D
Institut National de la Recherche Agronomique, INRA, UMR 1301, France.
Dubuffet
Aurore
A
Cazes
Dominique
D
Moreau
Sébastien
S
Drezen
Jean-Michel
JM
Poirié
Marylène
M
D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D004330:Drosophila / Q000201:enzymology / Q000276:immunology / Q000469:parasitology*; D005260:Female; D006458:Hemolymph / Q000201:enzymology; D006790:Host-Parasite Interactions; D007814:Larva / Q000201:enzymology; D008969:Molecular Sequence Data; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D016415:Sequence Alignment; D015843:Serpins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D014862:Wasp Venoms / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D014863:Wasps / Q000378:metabolism / Q000472:pathogenicity*
D011993:Recombinant Fusion Proteins; D015843:Serpins; D014862:Wasp Venoms; D014442:Monophenol Monooxygenase