How RNAi Works

siRNA Unzipping

RISC becomes activated when the double-stranded siRNA it contains is unzipped.

Unzipping siRNA requires energy provided by adenosine triphosphate (ATP).

An arrow labeled s-i-R-N-A unzipping, points from an assembly of R-I-S-C s-i-R-N-A to proteins and single strand of R-N-A labeled active R-I-S-C. A second curved arrow tangent the first arrow shows A-T-P converting to A-D-P + P-I.
siRNA unzips with energy from ATP, activating RISC