Targeted disruption of EMG1 in mice by homologous recombination. (A) Structure of the wild-type Emg1 locus, the targeting vector and the mutated locus with exons 2-6 replaced by SA-IRESβgeo cassette. The location of the hybridization probes (5' probe and 3' probe) for Southern blot analyses are shown. (B-C) Southern blot analysis of targeted ES cell clones using the 3' probe (B) and the 5' probe (C). (D) Whole mount X-gal staining of Emg1+/- embryos (E8.5 and E9).