Identification of parasite-responsive cysteine proteases in Manduca sexta.
Parasites have evolved different virulence strategies to manipulate host physiological functions. The parasitoid wasp Cotesia congregata induces developmental arrest and immune suppression of its Lepidopteran host Manduca sexta. In this interaction, a symbiotic virus (C. congregata Bracovirus, CcBV) associated with the wasp is essential for parasitism success. The virus is injected into the host with wasp eggs and virus genes are expressed in host tissues. Among potential CcBV virulence genes, cystatins, which are tight binding inhibitors of C1A cysteine proteases, are suspected to play an important role in the interaction owing to their high level of expression. So far, however, potential in vivo targets in M. sexta are unknown. Here, we characterized for the first time four M. sexta C1A cysteine proteases corresponding to cathepsin L and cathepsin B and two different '26-29 kDa' cysteine proteases (MsCath1 and MsCath2). Our analyses revealed that MsCath1 and MsCath2 are transcriptionally downregulated in the course of parasitism. Moreover, viral Cystatin1 and MsCath1 co-localize in the plasma following parasitism, strongly suggesting that they interact. We also show that parasitism induces a general increase of cysteine protease activity which is later controlled. The potential involvement of cysteine proteases in defense against parasitoids is discussed.
Institut de Recherche sur la Biologie de l'Insecte, Université François Rabelais, UMR CNRS 6035, Faculté des Sciences et Techniques, Parc de Grandmont, INSERM U 618, F-37200 Tours, France.
Céline
C
Serbielle
Sébastien
S
Moreau
Florian
F
Veillard
Emilien
E
Voldoire
Annie
A
Bézier
Marie-Anne
MA
Mannucci
Anne-Nathalie
AN
Volkoff
Jean-Michel
JM
Drezen
Gilles
G
Lalmanach
Elisabeth
E
Huguet
D000818:Animals; D015891:Cystatins / Q000235:genetics / Q000378:metabolism*; D003546:Cysteine Endopeptidases / Q000032:analysis / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D006790:Host-Parasite Interactions; D019476:Insect Proteins / Q000032:analysis / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D007814:Larva / Q000201:enzymology / Q000254:growth & development; D018402:Manduca / Q000201:enzymology / Q000469:parasitology*; D018071:Polydnaviridae / Q000201:enzymology*; D014863:Wasps / Q000502:physiology* / Q000821:virology
D015891:Cystatins; D019476:Insect Proteins; D003546:Cysteine Endopeptidases