Fig. 1. Targeted generation of MLC2a-null mice. (A) Targeting strategy. A restriction map of the relevant genomic region of MLC2a (top), the targeting vector for MLC2a (middle) and the mutated/targeted locus after recombination (bottom) are shown. The translational start site is indicated by ATG. Orientations of Cre and neomycin resistance genes (Neo) are indicated by arrows. A, Acc1; B, BamH1; H, HindIII; K, Kpn1; S, Sst1; X, Xba1. (B) Detection of wild-type and targeted alleles by Southern blot analysis. DNA from electroporated MLC2a ES cells was digested with Sst1 and analyzed by Southern blot analysis with a probe as shown in A. The 9.5 and 7.5 kb bands represent wild-type and targeted alleles, respectively. (C) Detection of MLC2a by protein analysis. Proteins were prepared from E9.5 MLC2a-null (–/–) and wild-type (+/+) embryos, and analyzed with MLC2a antibodies.