The allele was created to have the human BEST1 promoter/enhancer regions directing the expression of a CreER(T2) fusion gene. The targeting vector contained, from 5' to 3', the human BEST1 promoter (nucleotides -585 to +38), followed by a CreER(T2) fusion gene, and an SV40 a polyA cassette. The plasmid was pronuclear injected into C57BL/6J(attPx3) zygotes along with phiC31 integrase mRNA. The resulting founder mice were bred with C57BL/6J for germline transmission. (J:305495)