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Protein tyrosine phosphatases of Toxoneuron nigriceps bracovirus as potential disrupters of host prothoracic gland function
Author(s) -
Falabella Patrizia,
Caccialupi Pasqua,
Varricchio Paola,
Malva Carla,
Pennacchio Francesco
Publication year - 2006
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/arch.20120
Subject(s) - biology , heliothis virescens , ribosomal protein s6 , braconidae , noctuidae , phosphorylation , host (biology) , parasitoid , protein kinase a , protein phosphorylation , microbiology and biotechnology , lepidoptera genitalia , genetics , botany
The genomic sequence of the bracovirus associated with the wasp Toxoneuron nigriceps (Hymenoptera, Braconidae) ( Tn BV), an endophagous parasitoid of the tobacco budworm larvae, Heliothis virescens (Lepidoptera, Noctuidae), contains a large gene family coding for protein tyrosine phosphatases (PTPs). Here we report the characterization of cDNAs for two of the viral PTPs isolated by screening a cDNA library from haemocytes of parasitized host larvae. The two encoded proteins show 70% amino acid identity and are expressed in the fat body of parasitized hosts. In addition, one was expressed in inactivated prothoracic glands (PTGs), 24 h after parasitoid oviposition. The rapid block of ecdysteroidogenesis does not appear to be due to inhibition of general protein synthesis, as indirectly indicated by the unaltered S6 kinase activity in the cytosolic extracts of basal PTGs from parasitized host larvae. Rather, Tn BV PTP over‐expression in inactivated host PTGs suggests that gland function may be affected by the disruption of the phosphorylation balance of key proteins regulating points upstream from the ribosomal S6 phosphorylation in the PTTH signaling cascade. Arch. Insect Biochem. Physiol. 61:157–169, 2006. © 2006 Wiley‐Liss, Inc.