An arginine to tryptophan (C-to-T change at position 733 and C-to-G change at position 735) substitution was introduced at residue 245 (p.R245W) in exon 7. In addition, a loxP site, Trp53 exons 7-11 with a native polyadenylation signaling sequence, and FRT site flanked PGK neomycin resistance gene cassette and second loxP site were inserted in intron 6. (J:268678)