Targeting of ES cells to generate a floxed calponin-3-GFP knock-in.

<p>A. Schematic illustration of the <i>Cnn3</i> locus, the targeting construct and the <i>Cnn3</i> locus after targeting. The targeting strategy aimed at replacing exons 2 to 5 with a floxed mini gene corresponding to exons 2 to 7 fused to a GFP-cDNA. Exons and the mini gene are represented by grey boxes, the neomycin-resistance gene is illustrated by a white box. LoxP-sites are depicted as black triangles, FRT-sites as white triangles. Restriction sites for the enzymes used for southern blot analysis are indicated. Please note that the illustration is not in scale. B. Southern blot analysis of the targeted clone used for blastocyst injection. Genomic DNA was digested by NcoI, HindIII, BamHI or KpnI, respectively, separated by agarose gel electrophoresis and blotted. The blot was hybridized with the internal 5’- and the external 3’-probe as indicated in A. Arrows indicate the positions of fragments corresponding to the non-targeted as well as the targeted allele.