Figure 1.

Targeted dominant-negative mutation of mouse Ptn gene. (A) Restriction map of a part of the mouse Ptn gene, the targeting vector, and the structure at the mutated locus following the homologous recombination. The coding exons are depicted by black boxes and are numbered. Genomic fragments from the Ptn gene and neomycin gene used as probes for Southern blotting are depicted as hatched boxes (probe A and probe N); arrows denote PCR primers (B, C, D, E, and N) used for genotyping the ES cells and the chimeric animals. Neo, the neomycin transferase gene; TK, thymidine kinase gene; arrows depict the transcriptional orientation of these genes. Only relevant restriction sites are shown: K, KpnI; S, SmaI; X, XhoI; E, EcoRI; H, HindIII; B, BamHI. (B) Southern blot analysis of genomic DNA extracted from the tails of the sterile, highly chimeric mice with a Ptn dominant-negative mutation and normal highly chimeric mice without Ptn gene disruption. The DNA was digested with EcoRI and hybridized with probe A. The sizes of wt (W.T.) and disrupted (K.O.) alleles are shown. (C) PCR amplification products of the DNA extracted from the mouse tails. The sizes of amplification products of wt (W.T.) and disrupted (K.O.) alleles are shown.