A targeting construct was designed to insert an enhanced green fluorescent protein sequence (EGFP) sequence (preceded by sequence for linker peptide CKDPPVAT) and a loxP-flanked neomycin (neo) resistance sequence-STOP cassette in the 3' UTR. Subsequent cre-mediated recombination removed the floxed neo-STOP cassette. This allele expresses a chimeric protein with the EGFP peptide linked to the C-terminus of the endogenous peptide. (J:168822)