Comparison of dsRNA, siRNA and shRNA uptake and efficiency in insect cells

In insect systems, long double stranded RNA (dsRNA) is widely used to trigger RNA interference (RNAi) and knockdown genes. Usage of short interference RNA (siRNA) and short hairpin RNA (shRNA) are limited due to variability of their effect depending on the designed specific sites targetting and possible uptake problem. Here, we compared the potency of si/shRNA and dsRNA in CPB cells. In CPB cells, si/shRNA was unable to trigger RNAi. With the help of transfection reagent, si/shRNA was able to trigger RNAi in CPB cells. Confocal observations of Cy3 labeled-si/shRNA cellular uptake revealed reduced uptake of si/shRNA compared to dsRNA. Finally, we show that long dsRNA fused si/shIAP effectively trigger RNAi in CPB cells, suggesting that the length of si/shIAP is critical parameter. Our results show that CPB cells are unable to uptake short length si/shRNA and this leads to ineffective RNAi response.