Molecular characterization of human Argonaute-containing ribonucleoprotein complexes and their bound target mRNAs.
microRNAs (miRNAs) regulate the expression of mRNAs in animals and plants through miRNA-containing ribonucleoprotein particles (RNPs). At the core of these miRNA silencing effector complexes are the Argonaute (AGO) proteins that bind miRNAs and mediate target mRNA recognition. We generated HEK293 cell lines stably expressing epitope-tagged human AGO proteins and other RNA silencing-related proteins and used these cells to purify miRNA-containing RNPs. Mass spectrometric analyses of the proteins associated with different AGO proteins revealed a common set of helicases and mRNA-binding proteins, among them the three trinucleotide repeat containing proteins 6 (TNRC6A,-B,-C). mRNA microarray analyses of these miRNA-associated RNPs revealed that AGO and TNRC6 proteins bind highly similar sets of transcripts enriched in binding sites for highly expressed endogenous miRNAs, indicating that the TNRC6 proteins are a component of the mRNA-targeting miRNA silencing complex. Together with the very similar proteomic composition of each AGO complex, this result suggests substantial functional redundancy within families of human AGO and TNRC6 proteins. Our results further demonstrate that we have developed an effective biochemical approach to identify physiologically relevant human miRNA targets.
Landthaler
Markus
M
Laboratory of RNA Molecular Biology, Howard Hughes Medical Institute, The Rockefeller University, New York, New York 10065, USA.
Gaidatzis
Dimos
D
Rothballer
Andrea
A
Chen
Po Yu
PY
Soll
Steven Joseph
SJ
Dinic
Lana
L
Ojo
Tolulope
T
Hafner
Markus
M
Zavolan
Mihaela
M
Tuschl
Thomas
T
D002460:Cell Line; D039642:Eukaryotic Initiation Factors / Q000378:metabolism*; D006801:Humans; D047468:Immunoprecipitation; D035683:MicroRNAs / Q000378:metabolism; D020543:Proteome; D012333:RNA, Messenger / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism; D014162:Transfection
D039642:Eukaryotic Initiation Factors; C531907:MIRN122 microRNA, human; D035683:MicroRNAs; D020543:Proteome; D012333:RNA, Messenger; D012261:Ribonucleoproteins