The L1L2_Bact_P cassette is inserted downstream of exon 2, creating a 3581 bp deletion of exons 3-5. The cassette is composed of an FRT site followed by lacZ sequence and a loxP site. This first loxP site is followed by a neomycin resistance gene under the control of the human beta-actin promoter, SV40 polyA, a second FRT site and a second loxP site. Flp-mediated recombination removed the lacZ sequence and the neo cassette. (J:311543)