A composite fluorescent reporter/recombinase cassette was introduced to exon 1 of the gene. The targeting vector incorporated rabbit beta-globin (exon 2-3 partial genomic sequence serving as an artificial intron and splicing donor/acceptor), EYFP fluorescent reporter, encephalomyocarditic virus (EMCV) internal ribosome entry site (IRES), P1 phage cre recombinase cDNA optimized for mammalian cells (hCre; iCre), bovine growth hormone (bGH) poly-adenylation signal (pA), and a floxed neomycin resistance cassette. Cre-mediated recombination removed the floxed neo cassette. (J:247962)