Figure 1.

Generation of CYP26 mutant mice. (A) Targeting strategy. Homologous recombination between the wild-type CYP26 allele (exons are shown as solid boxes) and the targeting vector generates an insertional allele (CYP26^neo). A null allele (CYP26⁻) was created by subsequent Cre-mediated deletion of the indicated region located between lox P sites. (C) ClaI; (N) NsiI; (RV) EcoRV; (S) SalI; (X) XhoI; (DT) a diphtheria toxin-resistance cassette. (B) Southern blot analysis of offspring obtained from intercrossing of CYP26^neo/+ heterozygotes. Genomic DNA were digested with both NsiI and ClaI, and EcoRV, the resulting fragments were subjected to hybridization with the 5′ probe and the 3′ probe indicated in A, respectively. The sizes of hybridizing fragments are indicated in kilobases. (C) PCR analysis with a mixture of the three primers (P1, P2, and P3) shown in A of offspring obtained from intercrossing of CYP26^+/− heterozygotes. The sizes of PCR products are shown in base pairs.