Figure 6. A scheme for gene and enhancer trapping for the Gal4-UAS system.
A gene trap or an enhancer trap construct containing gal4 is injected into fertilized eggs with the transposase mRNA. Injected founder fish are raised and mated with UAS:GFP reporter fish. When gal4 is expressed under the control of an endogenous promoter/enhancer, GFP expression is induced in the F1 embryos via the Gal4-UAS system. Double transgenic F1 embryos express GFP in spatially and temporally restricted fashions may be picked up.