Identification, amplification and characterization of miR-17-92 from canine tissue

Recently, a novel group of genes encoding small RNA molecules, termed microRNAs (miRNAs), has been discovered to play a vital role in eukaryotic gene expression. Known to act in a post-transcriptional fashion, miRNAs can inhibit translation by binding to messenger RNA (mRNA) or by targeting mRNA for degradation. A search of genetic databases revealed significant conservation of miRNA genes between the domestic dog and the human. This finding suggests that expression patterns may also be conserved. Proof of principle experiments, including serial dilutions and sequencing, were performed to verify that primers made to amplify human mature miRNAs can be used to amplify canine miRNAs, providing that the mature sequences are conserved. TaqMan® Real-time PCR techniques were used to isolate the first miRNA mature products from canine tissues. The expression levels of miR-17-3p, miR-17-5p, miR-18, miR-19a, miR-19b, miR-20, and miR-92 were evaluated in five canine tissues (heart, lung, brain, kidney, and liver) using the delta-delta Ct (critical threshold) method.