(B) Southern analysis of the RanBP2 locus of wild-type and heterozygous genomic DNA of tails of F1 mice digested with PpuMI (left panel) and HindIII (right panel) with probes at the 3′ (left panel) and 5′ (right panel) flanking regions of the insertion breakpoint. Q1 is a cosmid containing the RanBP2 gene up to exon 20 [4].