FIG. 2.
Disruption of the mouse MrgX locus by gene targeting. (A) Genomic structure of the mouse MrgX gene and the targeting vector used to generate the conditionally targeted allele of MrgX. The targeting vector was constructed by flanking a 2.2-kb region containing the MrgX coding exon by two loxP sites with a PGK-neo cassette. The regions of homology consist of a 3.4-kb region for the 5′ arm and a 3-kb region for the 3′ arm, respectively. The MC1tk cassette was located next to the 3′ homology arm. The probe fragments for genotyping are indicated as shaded boxes at the bottom. Abbreviations: E5, EcoRV; E1, EcoRI; H3, HindIII; C1, ClaI; B1, BamHI. (B) Southern blot analysis of tail DNA from pups at weaning from breeding pairs containing the recombinant (floxed) allele (MX9-1) and the MrgX-deleted [Δ (−)] allele (MX13-1). Genomic DNAs were digested with EcoRV or EcoRI and hybridized with 5′ or 3′ probes, respectively. WT, wild type. (C) Northern blot analysis of MrgX expression in wild-type (+), MrgX− (−), and MrgXFlox (floxed allele, F) males. EtBr staining of RNAs (28S and 18S) was used to demonstrate equal loading of samples.