The 5' UTR, start codon and first 26 amino acids in exon 2 was replaced with a neomycin resistance gene in reverse orientation. Two types of truncated transcript were detected in mutant testis or kidney of by RT-PCR, one having the undeleted region of exon 2 and full-length exon 3, and the other having exons 1 and 3, but not 2. Western blot failed to detect corresponding proteins for these transcripts, indicating that neither can be properly translated. (J:98434)