A loxP site was inserted into exon 22 downstream of the STOP codon. An FRT-flanked neomycin resistance cassette with a 3' loxP site was inserted into exon 22 downstream of the 1.1 kb sequence to be deleted from the 3' UTR, followed by three SV40 polyA signals. Flp-mediated recombination removed the selection cassette and cre-mediated recombination deleted the 1.1 kb sequence in the 3' UTR. RT-PCR confirmed the absence of transcripts with an intact 3' UTR. (J:222342)