EXPRESSION OF AN ANTISENSE DIHYDROFOLATE-REDUCTASE TRANSCRIPT IN TRANSFECTED MOSQUITO CELLS - EFFECTS ON GROWTH AND PLATING EFFICIENCY

Novel approaches to control of vector-borne disease include potential use of transgenic insects, in which molecular mechanisms will be induc ed to prevent transmission of pathogenic organisms. The infrastructure essential to this technology includes the cloning of essential genes from vector insects, and the development of efficient transformation s trategies. In this study, we use a continuous mosquito (Aedes albopict us) cell line and a cloned mosquito dihydrofolate reductase gene to de monstrate a transgenic approach that may be used to select for the pre sence or absence of particular gene functions in transfected cells. Pl asmids containing the dihydrofolate reductase gene in sense and antise nse orientation, under the regulation of a temperature-inducible promo ter, were expressed in stably transfected mosquito cells. At the norma l growth temperature of 28 degrees C, or after mild heat induction at 34 degrees C, expression of the dihydrofolate reductase construct in s ense orientation had little effect on cell growth. In contrast, recove ry of clones transfected with the antisense construct was reduced, and induction of antisense transcripts at 34 degrees C further compromise d cell growth and viability. Clones transfected with the sense constru ct retained significantly higher copy numbers of foreign DNA than did cells transfected with the antisense construct. These studies provide a basis for use of sense and antisense dihydrofolate reductase constru cts to recover transfected mosquito cells with specific desired phenot ypes, based on the relative expression of cloned genes of interest.