|Zhu, Yu cheng|
Submitted to: Insect Molecular Biology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/2/2006
Publication Date: 8/2/2006
Citation: Maddur, A.A., Liu, X., Zhu, Y., Fellers, J.P., Oppert, B.S., Park, Y., Bai, J., Wilde, G.E., Chen, M. Cloning and characterization of protease inhibitor-like cdnas from the hessian fly [mayetiola destructor (say)]. Insect Molecular Biology 15: 485-496. Interpretive Summary: Proteolysis, the breakdown of proteins into smaller peptides or amino acids by proteinases, is involved in various biological processes such as food digestion, growth regulation, and immunity. Abnormal proteolysis can cause disease or even death in Humans. In insects, proteolysis regulates morphogenesis and immunological reaction to the invasion of pathogens. Therefore, proteolysis is strictly regulated in all organisms. One of the critical mechanisms for regulation of proteolysis is through the inhibition of proteinases by proteinase inhibitors. Therefore, understanding the regulation of proteolysis through proteinase inhibitors has the potential to find ways to disrupt proteolysis in insects, resulting in either insect death or weakened immunity. In this research, we report the identification and characterization of a network of proteinase inhibitors from the Hessian fly (Mayetiola destructor), one of the most destructive insects of wheat.
Technical Abstract: Analysis of transcriptomes from the salivary glands and midgut of Hessian fly [Mayetiola destructor (Say)] larvae identified a set of diverse cDNAs that encode proteins with a relatively high percentage (over 10%) of cysteines. Structural comparison of these putative proteins with known sequences in GenBank revealed that the positions of the cysteines in the identified proteins were highly conserved within a family of proteinase inhibitors despite very little overall sequence similarity. Phylogenetic analysis sorted this set of cDNAs into five different groups. To determine if these cDNAs indeed encode proteinase inhibitors, recombinant proteins were generated with 2 cDNAs from 2 different groups. Biochemical analysis of the recombinant proteins against commercial and insect gut proteinases demonstrated that the recombinant proteins are strong proteinase inhibitors with different specificities. Northern blot and real-time PCR analysis revealed that the different genes were expressed at different developmental stages and in different tissues. The overall results indicated that Mayetiola destructor contains a complex of genes that code for proteinase inhibitors which may regulate proteinase activities in different regulatory pathways.