Figure 1.
Strategy for deleting Area I-II-III within Pdx1. (Top) Pdx1 genomic structure. Area I-II-III lies ∼2 kb 5′ of the transcription start site. Homologous recombination with the targeting vector generated the frt-neo allele; Flp deletion created the flox I-II-III allele; subsequent Cre deletion led to the ΔI-II-III allele. (Black boxes) Exons; (gray box) B-X external probe for Southern blot analysis (diagnostic band lengths pre/post-recombination indicated). (neoR) Neomycin resistance cassette; (TK) thymidine kinase cassette. Black and white arrowheads indicate LoxP and FRT sites, respectively. (B) BamHI; (Bs) BstEII; (P) PstI; (RV) EcoRV; (X) XbaI.