Aedes aegypti dopa decarboxylase: gene structure and regulation

Dopa decarboxylase converts L-dopa to dopamine, a precursor molecule for di verse biological activities in insects including neurotransmission and a va riety of tanning reactions required for development, reproduction and defen ce against parasites. Herein, we report the cloning and sequencing of the A edes aegypti Ddc gene, including 2.1 kb of the upstream promoter region. Th e transcribed region of the gene spans more than 16 kb and contains five ex ons. In site hybridization localizes the blood-meal-induced ovarian transcr iption of this gene to the follicular epithelial cells surrounding individu al oocytes. Ovary tissue transcription of Ddc is increased in response to i njection of 20-hydroxyecdysone to levels equal to those observed for blood- fed controls, however coinjection with the translational inhibitor cyclohex imide negates the effect, indicating an indirect regulatory role for this h ormone. Clusters of putative ecdysone-responsive elements and zinc-finger b inding domains for the products of Broad-Complex gene family are identified in the 5'-promoter region. These elements are discussed in the context of common insect Ddc regulatory mechanisms.