Exon 9 was replaced with a frt-flanked puromycin resistance cassette and a modified exon 9 in which nucleotide substitution(s) result(s) in the amino acid substitution of serine for cysteine at position 433 (C433S). This mutation abolishes the prenylation at the site. Flp-mediated recombination removed the selection cassette. (J:208379)