Insects protect themselves from mechanical injury and predators by enveloping themselves in a chitinous cuticle and lining their guts with a peritrophic matrix (PM) made up of chitin and protein. Several isoforms of the enzyme that makes chitin, chitin synthase (CHS), are generated by multiple genes and alternate exon splicing. This study will determine the role of these CHS isoforms in the synthesis of the cuticle and the PM. The red flour beetle, Tribolium castaneum, will be used to examine at the whole insect level how the activities of CHS genes are coordinated and regulated to ensure proper insect development. To understand the role of each CHS in embryonic, larval and adult cuticle and PM, the investigators will inactivate each gene in whole insects using interfering RNAs specific for each gene and determine the effects on cuticle and PM integrity at each stage of insect development. At the molecular level, the investigators will produce large amounts of each CHS or their catalytic domains and determine their biochemical properties including susceptibility to various chitin inhibitors. Knowledge generated in this proposal with Tribolium will lead to greater general understanding of chitin metabolism and its influence on insect development. CHS is the target protein of some insecticides and the results of this study will provide useful information for the design of additional strategies to control insect pests in agriculture and disease vectors, while minimizing detrimental effects on the environment. This award will also assist ongoing efforts by the investigators to maintain the popular website, Tribolium Genetics Website; to respond to requests for Tribolium stocks, information and advice; and to conduct outreach activities involving K-12 students and biology teachers.
