Figure 1.

SCL-lacZ gene targeting strategy. (A) The SCL-lacZ targeting vector is shown above the map of the SCL genomic locus. Regions of homology where recombination occurred are indicated as crosses and the correctly targeted locus is depicted below. Exons are shown as numbered, solid boxes. The positions of the E. coli lacZ gene (lacZ), the polyadenylation signal (pA), and the PGKneo cassette (neo) are indicated. Abbreviations: B, BamHI; R, EcoRI; S, SacI; X, XbaI. (B) Southern hybridization of BamHI-digested DNA from wild-type (w/w) and heterozygous (lacZ/w) mice hybridized with probe A, indicating germ-line (5 kb) and targeted (3 kb) alleles.