The shRNA-coding plasmid can inhibit the artificial target gene in BHK-21 cells. The shRNA-coding plasmid PB-N3D2B was co-transfected with the fusion GFP-expressing plasmid, pEFGP-Target, at different ratios (0:1, 1:1, 0.5:1, and 0.25:1). The mRNA levels of GFP were measured by qPCR. (A) One amplification plot of three separate experiments is shown. The y-axis represents the PCR relative fluorescence units at the wavelength of 465 to 510 nm. The cycle number is displayed on the x-axis. (B) Cycle threshold (CT) values are derived from the amplification profiles shown in panel A. (C) The suppression ratio of different amounts of PB-N3D2B compared to the control with no PB-N3D2B (transfection ratio 0:1) is shown. The data represent the means ± SEM of three separate experiments.