1. RNA interference: Kill the messenger!

7. conclusion: dsRNA triggers potent and specific gene silencing inject worms with dsRNA corresponding to a gene involved in wiggling (unc-22) Discovery

8. Biochemistry to Examine Structure short interfering RNA: siRNA 21 nt long, dsRNA: P P

9. Dicer generates siRNAs RNase III endonuclease Mix cell extract with dsRNA 21-mer Berstein et al. Nature (2001)

10. RNA interference (RNAi) dsRNA siRNA Dicer RISC AAAA cap mRNA AAAA cap mRNA

11. Timeline 1998 1999 2000 2001 2002 1990 cosuppression of purple color in plants dsRNA injection in worms short RNAs identified in plants RNAi shown in vitro RISC activity partially purified siRNAs identifiedDicer identified RNAi used against HIV genome-wide RNAi screens begin

12. Big Potential for Small RNAs Adapted from Ryther et.al. Gene Therapy (2005)

14. S2 Drosophila cells spread on coated glass surface via lamellipodia

15. Example of RNAi experiment