Figure 3.

Two‐step model to explain the efficiency of siRNA (s: sense strand, as: antisense strand): 1) Depending on the relative stability of the two ends of an siRNA, one of the two strands is preferentially assembled into the RISC. The retention of the strand complementary to the target RNA can be achieved through the selection of a suitable sequence. 2) An antisense strand assembled into the RISC can, however, be unsuitable for silencing when the complementary sequence of the target RNA is inaccessible. The local structure of the target region thus also influences silencing significantly. (Figure adapted from Ref. 48 with permission from Elsevier.)