Fig. 2.

Targeted disruption of the mouse Pf20 gene. (A) Schematic representation of the strategy used to disrupt Pf20. (a) Partial genomic structure of the Pf20 gene. (b) Structure of the targeting vector. (c) Structure of the mutated allele. Xb, XbaI; PGK, phosphoglycerate kinase; DT, diphtheria toxin; P1/P2, primers for amplifying the WT allele; P3/P4, primers for amplifying the mutant allele. (B) Southern blotting analysis of targeted ES cell clones. An external probe gave rise to a single 15-kb band in WT genomic DNA digested with XbaI and an 8.5-kb band in the mutant allele. (C) Genotyping by PCR. The WT allele yielded a 500-bp amplicon. A 700-bp amplicon representing the phosphoglycerate kinase-neo cassette was detectable only when a targeted allele was present.