A novel graphene oxide-based fluorescence assay for RNA endonuclease activity of mammalian Argonaute2 protein

A novel graphene oxide (GO)-based amplified fluorescence assay for RNA endonuclease activity of mammalian Argonaute2 (Ago2) was developed. Owing to the extraordinarily high quenching efficiency of GO, the probe labeled with a fluorophore carboxyfluorescein exhibits minimal background fluorescence, while strong fluorescence intensity is observed with the addition of Ago2-miRNA complex due to the scission of the target mRNA sequences and the release of FAM-linked oligonucleotide fragments. Furthermore, Ago2-miRNA complex may be released to initiate another cycle of cleavage. The newly designed simple and cost-effective method exhibits high sensitivity with a detection limit of 1.7 nM (3 sigma) for Ago2 endonuclease activity. (C) 2013 Elsevier B.V. All rights reserved.