FIGURE 1.

Targeting strategy for the generation of mutant mice with deletions of forebrain Dlx enhancers. (A) Strategy for the deletion of enhancer I56i. (B) Strategy for the deletion of enhancer I12b. Homologous recombination in embryonic stem cells was completed using a BAC targeting construct wherein the enhancer was replaced with a floxed neomycin cassette. Recombinant clones were transferred into a blastocyst to generate chimeric embryos. Mice positive for the recombinant Dlx loci were crossed with CRE mice to remove the neomycin cassette. Black arrows, transcriptional orientation of each gene; black triangles, lox p locations. A, AgeI; H, HindIII; S, SalI; E, EcoRI; EV, EcoRV; K, KpnI; X, XbaI.