JH biosynthetic enzymes in the mosquito Aedes aegypti

The biosynthesis of juvenile hormone (JH) and its neuroendocrine regulation are attractive targets for chemical control of mosquitoes. JH is synthesized and secreted by a pair of small endocrine glands, the corpora allata (CA). JH plays important roles in insect development, metamorphosis and reproduction. In the JH synthetic pathway, farnesyl pyrophosphate (FPP) is synthesized from acetyl-CoA via the mevalonate pathway and is converted to JH via a specific pathway of isoprenoid-derived metabolites. HMG-CoA synthase (HMGS), HMG-CoA reductase (HMGR), and farnesyl diphosphate synthase (FPPS) are enzymes involved in isoprenoid biosynthesis and could be important in the regulation of JH levels. This project aims to isolate and characterize the gene(s) products of HMGS, HMGR, and FPPS in the CA of the mosquito Aedes aegypti. We have identified and cloned the cDNAs for AaHMGS, AaHMGR and AaFPPS in expression vectors.  Recombinant proteins were purified using metal affinity chromatography. The enzymatic activities of recombinant proteins and CA extract were measured using a newly developed assay utilizing fluorescent tags. Completion of the molecular, structural and functional analysis of the enzymes AaHMGS, AaHMGR and AaFPPS is important to improve our understanding of the regulation of the JH synthetic pathway in Aedes aegypti.