Figure 2.
Mapping and positional cloning of wrfr. (A Right) Physical map of the wrfr critical region, with the position of known genes indicated. (A Left) Northern blot with mRNA from normal and wrfr −/− skin was probed with RT-PCR products from known genes and GAPDH. No Slc27a4/FATP4 mRNA was detected in wrfr −/− skin, although it was readily detectable in normal skin. (B) PCR amplification of Slc27a4 exon 3. A PCR product ≈225 bp larger than that observed in wild type was amplified from all wrfr +/− and −/− DNAs. (C) Sequencing of Slc27a4 exon 3 from wrfr −/− mice revealed a 230-bp B2-type retrotransposon insertion with a 40-bp poly(A) tail. Fifteen base pairs of Slc27a4 were duplicated after insertion, generating a direct repeat. (D) Southern blot of ScaI-digested genomic DNA from wrfr +/+, +/−, and −/− mice was probed for Slc27a4. An ≈900-bp ScaI fragment was detected in normal mice, and an ≈1,150-bp fragment was detected in wrfr −/− mice. Both fragments were present in heterozygous mice.