Exon 12 was replaced with one in which the ATPase inhibitory site was mutated (523Lys-524Val- 525Thr-526Ser-527Pro-528Thr-529Lys in exon 12 was changed to encode 523Gln-524Leu-525Thr-526Thr-527Cys-528Thr-529Ser). A neomycin resistance cassette and red fluorescent protein were inserted downstream of the modified exon 12. (J:202998)