Exons 2 through 5 were floxed. An inserted neomycin resistance cassette was removed by Flp-mediated recombination. When Cre recombinase is introduced, exons 2-5 will be excised and the 5-GFP and 3-GFP components will be joined and expressed. The expression of the GFP reporter will be driven by the pCAG promoter. (J:262124)