Generation of the Cyp2a(4/5)bgs-null mouse model. (A) breeding strategy. (B) identification of the #28-2 pup as harboring the Cyp2s1−/Cyp2a5− (double-knockout) allele. PCR detection of the Cyp2s1− and Cyp2a5− alleles was performed as described in methods. Representative Cyp2s1+/Cyp2a5- (lane 1) and Cyp2s1−/Cyp2a5+ (lane 3) samples, and the sample for the #28-2 pup (lane 2), are shown. (C) characterization of the Cyp2a(4/5)bgs-null allele. Genomic DNA from WT, Cyp2s1-Cyp2a5Δ/+, and Cyp2s1-Cyp2a5Δ/Δ mice was analyzed, using PCR primers for Cyp2a4, Cyp2a5, Cyp2g1, Cyp2b10, Cyp2s1, Cyp2s1-Cyp2a5Δ, and Cre. Selected bands of a 100-bp DNA size marker are shown.