An IRES-Cre-SV40pA and FRT-flanked neo cassette was inserted 52 bp downstream of the stop codon into exon 18. Crossing with mice expressing Flp recombinase removed the neo. Northern blot showed expression of a shorter transcript than wild-type, indicating that the wild-type transcript contains a long 3' UTR, which was truncated by the insertion of the SV40 after the Cre.