Targeted disruption of the EKLF gene. (a) Targeting strategy. Solid boxes denote exons 1, 2, and 3. Gray boxes represent probes used in Southern blot analysis. Exons 2 and most of exon 3 were deleted in a targeted allele, effectively removing 239 amino acids of the 358-amino acid protein.21 (b) Southern blot analysis of EKLF+/+ and EKLF+/− ES cell clones using HindIII digestion and probe B. The 4-kb fragment represents the WT allele and the 3 kb represents the targeted allele. (c) Southern blot analysis using HindIII digested DNA from EKLF+/− and EKLF−/− ES cells derived by selection in elevated G418, using probe B. Hybridizations with probe A and a Neo probe confirmed that a homologous recombination event had occurred (data not shown).