Fig. 1.

Targeted disruption of the single exon syncytin-B gene. (A) Structure of the WT (wt) locus, the targeting vector, the targeted recombinant allele (r), the conditional allele, and the deleted KO syncytin-B allele. The loxP and FRT recombination sites (filled and empty red triangles, respectively), the BglI restriction sites, the probe for Southern blot analysis, and the R1–R4 primers for PCR genotyping are indicated. (B) Southern blot analysis of the DNA from wt ES cells and from the recombinant (r/wt) clone used to establish the recombinant mouse line. BglI-restricted DNA yielded 10.8-kb and 7.4-kb bands for the WT and recombinant alleles, respectively, with the probe in A. (C) PCR-based genotyping of mice, with the R3–R4, R1–R2, and R1–R4 primer pairs in A (fragments <500 bp shown).