Schematic representation of the generation of Procr Lox mice and PCR genotyping. The Procr^Lox allele was obtained by homologous recombination. The Procr-deleted allele was obtained when the region of the Procr gene flanked by LoxP sites was deleted by Cre-recombinase (A). PCR A detects the Procr-deleted allele. The PCR fragment of the wild-type allele is too large to be detected. PCR B detects the EPCR exon 1 wild-type allele. The Procr^Lox allele also generates a band that is 36 base pair (bp) smaller due to the replacement of 68 bp in the promoter with the 32-bp LoxP site. PCR C detects the promoter region wild-type allele that does not have the LoxP site inserted. Mox2Cre primers detect the Cre allele. Procr^–/–Meox2^+/cre pups were born at near Mendelian ratio (43 of 193 pups; 22.3% frequency compared with the expected 25% frequency) (B).