The transgene construct is knocked into into 3UTR region a splice acceptor flanked puro cassette, CAG promoter, floxed stop cassette, FRT-flanked stop cassette, GCaMP3, and WPRE sequence. Flp-mediated recombination removed the FRT-flanked stop cassette. Cre-mediated recombination removed the floxed stop cassette. (J:297198)