• A Corrigendum to this article was published on 01 December 2009

This article has been updated


Small RNAs direct RNA-induced silencing complexes (RISCs) to regulate stability and translation of mRNAs1,2. RISCs associated with target mRNAs often accumulate in discrete cytoplasmic foci known as GW-bodies3. However, RISC proteins can associate with membrane compartments such as the Golgi and endoplasmic reticulum4. Here, we show that GW-bodies are associated with late endosomes (multivesicular bodies, MVBs). Blocking the maturation of MVBs into lysosomes by loss of the tethering factor HPS4 (ref. 5) enhances short interfering RNA (siRNA)- and micro RNA (miRNA)-mediated silencing in Drosophila melanogaster and humans. It also triggers over-accumulation of GW-bodies. Blocking MVB formation by ESCRT (endosomal sorting complex required for transport)6 depletion results in impaired miRNA silencing and loss of GW-bodies. These results indicate that active RISCs are physically and functionally coupled to MVBs. We further show that MVBs promote the competence of RISCs in loading small RNAs. We suggest that the recycling of RISCs is promoted by MVBs, resulting in RISCs more effectively engaging with small RNA effectors and possibly target RNAs. It may provide a means to enhance the dynamics of RNA silencing in the cytoplasm.

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Change history

  • 11 November 2009

    In this letter, statements regarding the functions of HPS4 and 1 have been altered from those initially published, A section of text has been inserted, a sentence was altered and a sentence was deleted. This has been corrected in both the HTML and PDF versions of the article.


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We thank R. Cagan, H. Folsch, P. Sharp, G. J. Hannon, Q. Liu, X. Wang, C. Horvath, G. Goshima, V. Helfand, M. Lowe, I. Hariharan, D. Bilder, J. Treisman, M. Siomi and J. Pham for reagents; H. Folsch, I. Fields, A. Komuro, and D. Harris for help with some of the experiments; H. Jiang for help with statistics and the Bloomington Stock Center and the Developmental Studies Hybridoma Bank for fly strains and antibodies. Y.S.L. was supported by a FRAXA postdoctoral Fellowship; J.J.C. was supported by the CMBD Training Grant and J.B.P. was supported by a Presidential Fellowship. This work was also supported by grants from the National Institutes of Health to E.J.S. (GM072830) and R.W.C. (GM77581, GM68743), and from a grant from the Korean BioGreen 21 Program to Y.S.L. (20070301034036).

Author information


  1. Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, IL 60201, USA.

    • Young Sik Lee
    • , Sigal Pressman
    • , Arlise P. Andress
    • , Kevin Kim
    • , Jamie L. White
    • , Justin J. Cassidy
    • , Xin Li
    • , Kim Lubell
    • , Kenji Nakahara
    • , Jonathan B. Preall
    • , Priya Bellare
    • , Erik J. Sontheimer
    •  & Richard W. Carthew
  2. College of Life Sciences and Biotechnology, Korea University, Seoul 136–713, Korea.

    • Young Sik Lee
    • , Do Hwan Lim
    •  & Ik Sang Cho
  3. Hokkaido University, North 9, West 9, Kita-ku, Sapporo 060–8589, Japan.

    • Kenji Nakahara
  4. Department of Biology, New York University, NY 10003, USA.

    • Xin Li
  5. Department of Microbiology & Immunology, Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, CA 94143, USA.

    • Priya Bellare


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Y.L., E.S. and R.C. planned the project; all of the authors performed experimental work, except for E.S. and R.C.; Y.L., S.P., A.A., K.K., J.W., J.C., D.L., I.C., K.N., J.P., E.S. and R.C. performed data analysis and Y.L. and R.C wrote the manuscript.

Competing interests

The authors declare competing financial interests. R.W.C. and E.J.S. own shares in Silentech Inc., which may gain financially from publication. R.W.C. and Y.S.L. have a patent application whose value may be affected by publication.

Corresponding authors

Correspondence to Young Sik Lee or Richard W. Carthew.

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