Promoter-directed expression of recombinant fire-fly luciferase in the salivary glands of Hermes-transformed Aedes aegypti

Molecular genetic analyses of biological properties characteristic of insec t vectors of disease, such as hematophagy and competence for pathogens, req uire the ability to isolate and characterize genes involved in these proces ses. We have been working to develop molecular approaches for studying the promoter function of genes that are expressed specifically in the adult sal ivary glands of the yellow fever mosquito, Aedes aegypti. Genomic DNA fragm ents containing cis-acting promoter elements from the maltase-like I (MalI) and Apyrase (Apy) genes were cloned so as to direct the expression of the reporter gene, luciferase (luc). The function of the promoters was assayed transiently in cultured insect cells and by germ-line transformation of Ae. aegypti. Mall and Apy DNA fragments consisting of at least 650 nucleotides (nt) of DNA immediately adjacent to the 5'-end of the initiation codon of the mosquito genes directed constitutive expression of the luc reporter gen e in cultured cells. When introduced into Ae. aegypti chromosomes, approxim ately 1.5 kilobases (kb) of each promoter were able to direct the predicted developmental-, sex- and tissue-specific expression of the reporter gene i n patterns identical to those determined for the respective endogenous gene s. (C) 1999 Elsevier Science B.V. All rights reserved.