(A) Disruption of the IL11Ra locus by homologous recombination. Genomic organization of the murine IL11Ra locus encoded by genomic phage clone λ11.452 is shown, with the exons indicated as boxes and numbered and the coding regions shown in black. Dashed lines indicate parts of locus IL11Ra2 that are not homologous with locus IL11Ra. Restriction enzyme sites for locus IL11Ra and IL11Ra252 are indicated. Sites unique to a particular locus are shown in bold. EcoRI (R), BamHI (B), Sac I (S), HindIII (H), and Sph I (Sp). Shown below is the targeting vector containing the 5′ and 3′ regions of homology and the cDNAs encoding neomycin transferase (NEO) and thymidine kinase (TK) and the recombinant IL11Ra locus. The probe used in Southern screening of embryonic stem cells and tail biopsies and the expected sizes of the endogenous IL11Ra (3.4 kb), targeted IL11Ra (5.2 kb), and endogenous IL11Ra2 (4.0 kb) loci after EcoRI restriction digest are indicated. (B) Southern analysis of EcoRI-digested genomic DNA extracted from a litter derived from a cross between heterozygous IL11Ra+/− mice showing heterozygous, homozygous IL11Ra−/−, and wild-type IL11Ra+/+ mice. Sizes of the endogenous IL11Ra (3.4 kb) and the targeted IL11Ra (5.2 kb) loci are indicated, as is the band for the IL11Ra2 locus (4.0 kb).
