Fig. 1. Inactivation of the Dp1 locus. (A)The Dp1 locus is shown with the indicated coding exons and restriction enzyme sites (E, EcoRI; X, Xba; N, EcoNI). A star denotes a polymorphic 129Sv EcoNI site not seen in the C57BL/6 strain. The targeting vector and mutant Dp1 allele are shown, in which part or all of exons 4-9 (hatched boxes) is deleted with the insertion of the neo^R gene in the opposite reading frame. A 5' external probe and a 3' internal probe (below the wild-type allele) used for Southern analysis and six primers (arrowheads) used for genomic PCR are shown. (B) Southern analysis with the 5' external probe and EcoNI digestion was performed on F2 animals to visualize an 8.5 kb wild-type C57BL/6 band and a 6.6 kb mutant 129Sv band. Only wild-type and Dp1^+/- F2 animals are recovered. (C) Genomic PCR on laser-captured embryos from microdissected decidua is shown.