Small RNAs function within the context of RNA-induced silencing complexes (RISCs) containing Argonaute (AGO) subfamily proteins. Experiments now show that human RISC assembly is uncoupled from dicing and is facilitated by ATP to load the small RNA duplexes but is not necessary to unwind them. The four human AGO proteins show no obvious structural preferences for small RNA duplexes in contrast to the situation in flies and worms where small RNAs are actively sorted into distinct AGO proteins according to their structural features.
- Mayuko Yoda
- Tomoko Kawamata
- Yukihide Tomari
