Exons 2 and 3 were excised following transient Cre expression, leaving a single loxP site in intron 1. Western blot showed only a 60 kDa protein was present in mutants and wild-type, while wild-type also had a 110 kDa protein. RT-PCR confirmed that exons 2 and 3 had been deleted. RACE-PCR indicated presence of 2 variant transcripts in mutants: one transcript including exon 1 and exons 4 to 18 and the other only exons 4-18.