C3PO, an endoribonuclease that promotes RNAi by facilitating RISC activation

Ying Liu, Xuecheng Ye, Feng Jiang, Chunyang Liang, Dongmei Chen, Junmin Peng, Lisa N. Kinch, Nick V. Grishin, Qinghua Liu

Research output: Contribution to journalArticle

158 Scopus citations


The catalytic engine of RNA interference (RNAi) is the RNA-induced silencing complex (RISC), wherein the endoribonuclease Argonaute and single-stranded small interfering RNA (siRNA) direct target mRNA cleavage. We reconstituted long double-stranded RNA- and duplex si RNA-initiated RISC activities with the use of recombinant Drosophila Dicer-2, R2D2, and Ago2 proteins. We used this core reconstitution system to purify an RNAi regulator that we term C3PO (component 3 promoter of RISC), a complex of Translin and Trax. C3PO is a Mg2+-dependent endoribonuclease that promotes RISC activation by removing siRNA passenger strand cleavage products. These studies establish an in vitro RNAi reconstitution system and identify C3PO as a key activator of the core RNAi machinery.

Original languageEnglish (US)
Pages (from-to)750-753
Number of pages4
Issue number5941
StatePublished - Aug 17 2009


ASJC Scopus subject areas

  • General

Cite this

Liu, Y., Ye, X., Jiang, F., Liang, C., Chen, D., Peng, J., Kinch, L. N., Grishin, N. V., & Liu, Q. (2009). C3PO, an endoribonuclease that promotes RNAi by facilitating RISC activation. Science, 325(5941), 750-753. https://doi.org/10.1126/science.1176325