Fig. 2. (A) Knockout strategy for deleting DMR2. DMR2 was deleted at the flanking BamHI sites and replaced by IRES:LacZ-neo (grey box). (B) Southern blots with EcoRI digestion and a probe spanning exon 2 distinguished the targeted (8.7 kb) and wild-type (16.5 kb) alleles. (C) Lac Z staining of E 17 embryos. CP, choroid plexus. Scale bar, 1 mm.