Reporter gene expression is induced inresponse to injection of complete Freund's adjuvant in late third instarlarvae (96-120hr). Younger animals do not express the reporter gene inresponse to the injection. From pupariation on, there is a gradualdecrease in the response to the challenge. In response to live bacteria, afaint response is seen in second instar larvae and a full response is seenin adults.
Adults are pricked with a sterile needle dipped in culture pellets of various living microorganisms (distinct bacterial strains, fungal spores or hyphae). The level of induction of the reporter gene varies with the microorganism tested. Pricking results in a low but clearly detectable expression of all antimicrobial genes and these genes are induced above the background level by specific classes of microorganism.
Reichhart
Carried in a plasmid, transformed into l(2)mbn cells and induction of the promoter by ecdysone treatment is assayed using Ecol\lacZ activity levels. Gram negative bacteria are the best inducers of Dpt gene expression in ecdysone-treated l(2)mbn cells.
Stably transfected into S2 cells and used as a reporter for imd pathway activity.
Strong induction of Ecol\lacZ gene expression after bacterial challenge.
Inducible expression is superimposed on that of the endogenous Dpt gene at the end of the third larval instar.
Induction of the transgene by immune challenge parallels that of the resident Dpt gene.