Schematic representation of the method used to detect NATs within a cDNA population. Total RNA is retro-transcribed into cDNA, which was then used as the template to produce complementary strands of the transcripts that showed homology with the primers added to the reaction. DNA-dependent DNA polymerase synthesised the complementary strands of the target genes, which are thus preserved from exonuclease degradation. All of the ssDNA will be degraded, leaving those transcripts with complementary strands intact. PCRs were then performed to detect whether the target gene was present. Red line: cDNA that will be protected by the synthesis of its complementary strand. HG: reference gene used as the positive internal control. GI: gene of interest, the gene for which the present of antisense was examined.