Screening of the shRNA library for identifying essential factors involved in RNAi pathway.

<p>(A) The first screening scheme and results of the shRNA library directed against human helicases and RNAi-related genes. The screening was performed in duplicate. (B) Results of control experiments for inhibitory effects on RNAi. Luciferase data before correction (upper panel), results of control experiments (middle panel), and data after correction (bottom panel) are shown. Clones #1, #2 and #46 are empty shRNA vector (negative control), and clone #24 is Ago2 (positive control). (C) Multi-target analysis using five shRNA vectors directed against various sites in DDX3 mRNA. #, clone that showed reduced cell proliferation. Data was shown as mean and S.D. (n = 3). *<i>P</i><0.05.