BAC RP23-392P11 containing the Slc32a1 (Viaat) locus was modified by homologous recombination by inserting a Cre-recombinase sequence followed by a stop codon and a polyadenylation sequence downstream of the start codon of the Slc32a1 (or Viaat) gene. After linearization, the BAC only contained Viaat and the truncated coding sequence of the actin-related protein 5 homolog (Actr5) gene. This modified 109 kb BAC was microinjected into fertilized FVB/N oocytes. Transgenic animals have similar expression levels of Slc32a1 and Actr5 to wild type mice. Founder line 2.1 was analyzed and propagated. (J:166851)