miRNA UPL probe assay. A. SYBR Green I assay for miR166. Negative control reactions (minus-RT and water) produced detectable amplicons after 40 PCR cycles. B. UPL probe assay for miR166. No fluorescence was detected in the negative control reactions after 45 cycles of PCR. C. UPL probe assay amplification products for miR166 separated by gel electrophoresis on 4% agarose showing specific and non-specific amplification bands obtained after 45 cycles of PCR. Arrowhead indicates the expected size of amplicons. 1, 20 ng RNA; 2, 2 ng RNA; 3, 200 pg RNA; 4, 20 pg RNA; 5, 20 ng RNA minus-RT control; 6, water control.