RNAi Factors Are Present and Active in Human Cell Nuclei

Cell Rep. 2014 Jan 16;6(1):211-21. doi: 10.1016/j.celrep.2013.12.013. Epub 2014 Jan 2.

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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Argonaute Proteins / metabolism*
  • Autoantigens / metabolism*
  • Cell Nucleus / metabolism*
  • Cytoplasm / metabolism
  • DEAD-box RNA Helicases / metabolism*
  • HeLa Cells
  • Humans
  • Protein Binding
  • RNA Interference*
  • RNA-Binding Proteins / metabolism*
  • Ribonuclease III / metabolism*

Substances

  • AGO2 protein, human
  • Argonaute Proteins
  • Autoantigens
  • RNA-Binding Proteins
  • autoantigen GW182, human
  • trans-activation responsive RNA-binding protein
  • DICER1 protein, human
  • Ribonuclease III
  • DEAD-box RNA Helicases