The molecular analysis of gene expression in insects, with the notable exception of Drosophila melanogaster, lags behind those in prokaryotes, yeast, and vertebrates. A well characterized insect system amenable to dissection at the molecular level is provided by the antibacterial response of lepidopteran insects. Resistance to infection in insects is accomplished largely via structural barriers that limit access to the hemocoel. If these structural barriers are disrupted via injury or attack, potential pathogens or parasites may gain access to the hemocoel. To survive these infections, insects have evolved a set of active secondary defenses that (i) limit hemolymph loss and heal wounds, (ii) detect and eliminate invaders, and (iii) protect the injured host while structural barriers and depleted defenses are restored. One component of the active defensive arsenal against bacteria is the regulated synthesis of antibacterial, hemolymph proteins. The long term goal of the proposed research is to discover molecular mechanisms regulating the expression of genes encoding insect antibacterial proteins. The present proposal focuses on transcriptional regulation of antibacterial protein genes, gene structure, and tissue specific expression. Specific objectives are: (1) to determine the contribution of transcriptional control to peptidoglycan regulation of fat body cecropin-like protein (CLP) and attacin-like protein (ALP) synthesis; (2) to isolate and characterize M. sexta genes encoding CLP and ALP; (3) to analyze secondary structural elements associated with CLP and ALP genes in naive and peptidoglycan-induced fat body; and (4) to determine whether established lepidopteran cell lines exhibit enhanced transcription from antibacterial protein genes and synthesize elevated levels of CLP and ALP in response to peptidoglycan elicitors. The proposed research will yield new information concerning (i) the insect host-pathogen/parasite interaction and (ii) the structure and regulation of insect genes. This knowledge may contribute to the management of insect vectors of human and animal disease.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM041753-02
Application #
3300131
Study Section
Tropical Medicine and Parasitology Study Section (TMP)
Project Start
1989-04-01
Project End
1992-03-31
Budget Start
1990-04-01
Budget End
1991-03-31
Support Year
2
Fiscal Year
1990
Total Cost
Indirect Cost
Name
Purdue University
Department
Type
Schools of Earth Sciences/Natur
DUNS #
072051394
City
West Lafayette
State
IN
Country
United States
Zip Code
47907
Dunn, P E; Bohnert, T J; Russell, V (1994) Regulation of antibacterial protein synthesis following infection and during metamorphosis of Manduca sexta. Ann N Y Acad Sci 712:117-30
Russell, V W; Dunn, P E (1991) Lysozyme in the midgut of Manduca sexta during metamorphosis. Arch Insect Biochem Physiol 17:67-80