Fig. 1. Generation of the talin 1 conditional allele. (A) Scheme of the targeting strategy. Homologous recombination of the targeting construct into the Tln1 gene introduced a loxP site (triangle) downstream of coding exon 5 and a floxed pgk-neo cassette upstream of the first coding exon (exon 2). CRE expression induced three recombination events: (1) Type II deletion: removal of the neo cassette (Tln1 fl/fl); (2) Type III deletion: removal of exons 1-4 (not shown); (3) Type I deletion: removal of pgk-neo and exons 1-4 (Tln1^-). Primers a, b and c were used for the PCR reactions shown in B. (B) Recombination pattern observed by PCR on DNA extracted from E14.5 and P2 wild-type (WT) and Tln1HSA-CREko mutant (MT) littermates. (Top row) A 707 bp band indicative of the recombined allele (Rec) was observed in samples from Tln1HSA-CREko mice. (Middle row) The presence of floxed (fl) and wild-type (wt) alleles was confirmed. (Lower row) The presence of CRE recombinase was confirmed.