PROJECT SUMMARY
Recent dramatic increases in the incidence of mosquito-borne diseases, like Malaria, Zika, Chikungunya and Dengue
Fever, and the wide-spread resistance of mosquitoes to insecticides emphasizes the need for new approaches for insect
control based on mosquito-specific agents. The discovery of such mosquito-specific control agents depends on continued
basic research on the biology of mosquitoes. Juvenile hormone (JH), an epoxidated sesquiterpenoid, is an essential
regulator of major developmental and life history events in insects. Insects and crustaceans originated from aquatic
pancrustacean ancestors that invaded terrestrial ecosystems over 450 million years ago. The Methoprene-tolerant (Met)
protein is the intracellular receptor for insect JHs. The ability of Met to respond to MF, the “crustacean JH”, suggests that
the role of Met in sesquiterpenoid signaling precedes the evolutionary separation of the hexapoda from the crustacean
lineages. To address the evolutionary and biological significance of MF epoxidation, we generated mosquitoes completely
lacking either of the two enzymes that catalyze the last steps of MF/JH biosynthesis and epoxidation, the methyl
transferase (JHAMT) and the P450 epoxidase CYP15 (EPOX). jhamt-/- larvae lacking both MF and JH died at the onset of
metamorphosis. While epox-/- mutants, which synthesized MF but no JH completed the entire life cycle. While epox-/-
adults are fertile, the reproductive performance of both sexes is dramatically reduced. Using these two lines of null mutant
mosquitoes, we will investigate how in the absence of JH, MF is sufficient to complete adult development. Our hypothesis
is MF is able to properly activate the gene networks that control mosquito larval development and metamorphosis.
Additionally, we will investigate the reproductive fitness cost in JH null females. We expect to recognize the molecular
mechanism underlying the differences in JH signaling in our three model lines (jhamt-/-, epox-/- and WT). Our two null
mutant mosquito lines provide a unique opportunity to explore the role of non-epoxidated versus epoxidated JHs in the
development and reproduction of insects. Completing the proposed research could lead to the identification of targets for
designing new, specific and affordable strategies suitable for mosquito control.