A construct containing a loxP site, the wild-type Gjb6 coding sequence, a frt-flanked neomycin resistance cassette, another loxP site, the Gjb6 coding sequence with a point mutation leading to a substitution of an alanine reside on position 88 by a valine residue (A88V), an IRES, and a lacZ gene with a nuclear localization signal replaced the endogenous locus. The neomycin resistance cassette was removed via flp-mediated recombination. Cre-mediated recombination was used to delete the wild-type Gjb6 coding sequence, leaving the A88V mutant Gjb6, IRES, and the NLS-lacZ. PCR confirmed the expression of the mutant.