Probable RNA helicase. Required for RNA-mediated gene silencing by the RNA-induced silencing complex (RISC). Required for both miRNA-mediated translational repression and miRNA-mediated cleavage of complementary mRNAs by RISC (By similarity). ATP + H2O = ADP + H(+) + phosphate Belongs to the DNA2/NAM7 helicase family. SDE3 subfamily.