GFP genotyping and assessment of fluorescence expression in GFP nude rats. (A) Organs from GFP positive animals visualized under a fluorescence dissecting microscope. (B) Confirmation of the GFP genotype by PCR. Homozygous GFP rats displayed a single band at 1050 bp (lane 3), whereas heterozygous rats exhibited bands at both 1050 and 799 bp (lanes 2, 7, and 11). Only a single band at 799 bp was amplified from non-GFP (wild type) rats. (C) GFP expression in different organs as estimated by quantitative RT-PCR and expressed as a relative fold change compared to the organ with the lowest expression (heart). Standard error bars are indicated on the columns.