Submitted to: Insect Molecular Biology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/28/2007
Publication Date: 6/30/2007
Citation: Prabhakar, S., Chen, M., Elpidina, E.N., Vinokurov, K.S., Smith, C.M., Marshall, J., Oppert, B.S. 2007. Sequence analysis and molecular characterization of larval midgut cDNA transcripts encoding peptidases from the yellow mealworm, Tenebrio molitor L.. Insect Molecular Biology 16: 455-468. Interpretive Summary: To use inhibitors of insect digest enzymes as part of an effective control strategy for beetle pests, more information is needed on insect digestive enzymes. Random sequences of genetic material from the gut of the yellow mealworm yielded over 50 genetic sequences for digestive enzymes. These sequences were analyzed and grouped by function. This information will be used to devise new pest control strategies based on inhibitors of digestive enzymes.
Technical Abstract: Peptidase sequences were analyzed in randomly picked clones from cDNA libraries of the anterior or posterior midgut or whole larvae of the yellow mealworm, Tenebrio molitor Linnaeus. Of a total of 1,528 sequences, 92 sequences encoded potential peptidases, from which 50 full-length cDNA sequences were obtained, including serine and cysteine proteinases and metallopeptidases. Serine proteinase transcripts were predominant in the posterior midgut, whereas transcripts encoding cysteine and metallopeptidases were mainly in the anterior midgut. Alignments with other proteinases indicated that 40% of the serine proteinase sequences were serine proteinase homologs, and the remaining were identified as either trypsin, chymotrypsin, or other serine proteinases. Cysteine proteinase sequences included cathepsin B- and L-like proteinases, and metallopeptidase transcripts were similar to carboxypeptidase A. Northern blot analysis of representative sequences demonstrated the differential expression profile of selected transcripts across five developmental stages of T. molitor. These sequences provide insights into peptidases in coleopteran insects as a basis to study the response of coleopteran larvae to external stimuli and to evaluate regulatory features of the response.