Fig 1.

Schematic representation of the parental and modified Col1A1 locus jmjd2b-egfp Flp-In. The parental locus consists of a neomycin resistance gene flanked by FRT sites (triangles) and a promoterless hygromycin resistance gene that lacks an ATG start codon [Hygro (no ATG)]. Correct FLPo-mediated insertion of the jmjd2b vector replaces the neomycin cassette with the TetO-controlled jmjd2b-egfp gene and converts the nonfunctional Hygro (no ATG) into a functional selection cassette (Hygro) by providing a phosphoglycerate kinase promoter and ATG (PGK-ATG). Binding sites of primers (arrows) used for the characterization of ES clones with correct Flp-In (primers P1 to P3) and transgene-specific qRT-PCR (primers P6 and P7) and the resulting amplicon sizes are indicated.