Fig. 6.
Targeting of the Ppp2r1a locus by homologous recombination. (A) Ppp2r1a targeting construct integrated into the wild-type Ppp2r1a locus (upper panel) by homologous recombination (lower panel). The stop cassette in intron 2 leads to abrogation of transcription. (B) Southern blot analysis of a successfully targeted ESC clone; a BamHI digest reveals a wild-type fragment of 13 kb, the targeted allele shows a 7 kb fragment with the 5′ and a 6.5 kb fragment with the 3′ external Southern probe. (C) PCR genotyping using three primers (P1, P2, P3) distinguishes between wild-type mice and mice carrying the targeted allele. (D) WISH analysis of embryos at E6.5 resulting from Ppp2r1a+/− inter-crosses shows absence of Ppp2r1a expression in homozygous Ppp2r1a−/− embryos. Scale bar: 200 µm.