title: RNAi factors are present and active in human cell nuclei.
abstract: RNAi is widely appreciated as a powerful regulator of mRNA translation in the cytoplasm of mammalian cells. However, the presence and activity of RNAi factors in the mammalian nucleus has been the subject of considerable debate. Here, we show that Argonaute-2 (Ago2) and RNAi factors Dicer, TRBP, and TRNC6A/GW182 are in the human nucleus and associate together in multiprotein complexes. Small RNAs can silence nuclear RNA and guide site-specific cleavage of the targeted RNA, demonstrating that RNAi can function in the human nucleus. Nuclear Dicer is active and miRNAs are bound to nuclear Ago2, consistent with the existence of nuclear miRNA pathways. Notably, we do not detect loading of duplex small RNAs in nuclear extracts and known loading factors are absent. These results extend RNAi into the mammalian nucleus and suggest that regulation of RNAi via small RNA loading of Ago2 differs between the cytoplasm and the nucleus.
authors.affiliation: Departments of Pharmacology and Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390-9041, USA.
authors.forename: Keith T
authors.initials: KT
authors.lastname: Gagnon
authors.affiliation: Departments of Pharmacology and Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390-9041, USA.
authors.forename: Liande
authors.initials: L
authors.lastname: Li
authors.affiliation: Departments of Pharmacology and Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390-9041, USA.
authors.forename: Yongjun
authors.initials: Y
authors.lastname: Chu
authors.affiliation: Departments of Pharmacology and Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390-9041, USA.
authors.forename: Bethany A
authors.initials: BA
authors.lastname: Janowski
authors.affiliation: Departments of Pharmacology and Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390-9041, USA. Electronic address: david.corey@utsouthwestern.edu.
authors.forename: David R
authors.initials: DR
authors.lastname: Corey
mesh_terms: D060565:Argonaute Proteins / Q000378:metabolism*; D001324:Autoantigens / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D053487:DEAD-box RNA Helicases / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D011485:Protein Binding; D034622:RNA Interference; D016601:RNA-Binding Proteins / Q000378:metabolism*; D043244:Ribonuclease III / Q000378:metabolism*; D000099253:Trans-Activation Responsive RNA-Binding Protein
chemical_list: D060565:Argonaute Proteins; D001324:Autoantigens; D053487:DEAD-box RNA Helicases; D016601:RNA-Binding Proteins; D043244:Ribonuclease III; D000099253:Trans-Activation Responsive RNA-Binding Protein; C466422:AGO2 protein, human; C465663:TNRC6A protein, human; C408087:DICER1 protein, human