Ubiquitin-dependent mechanism regulates rapid turnover of AU-rich cytokine mRNAs

Proc Natl Acad Sci U S A. 2002 Feb 19;99(4):1842-6. doi: 10.1073/pnas.042575699. Epub 2002 Feb 12.

Abstract

An AU rich element (ARE) in the 3' noncoding region promotes the rapid degradation of mammalian cytokine and proto-oncogene mRNAs, such as tumor necrosis factor-alpha, granulocyte-macrophage colony-stimulating factor (GM-CSF) and c-fos. Destabilization of ARE-mRNAs involves the association of ARE-binding proteins tristetraprolin or AUF1 and proteasome activity, of which the latter has not been characterized. Here, we show that the stability of a model short-lived mRNA containing the GM-CSF ARE was regulated by the level of ubiquitin-conjugating activity in the cell, which links ARE-mRNA decay to proteasome activity. Increased expression of a cytokine-inducible deubiquitinating protein (DUB) that impairs addition of ubiquitin to proteins fully blocked ARE-mRNA decay, whereas increased expression of a DUB that promotes ubiquitin addition to proteins strongly accelerated ARE-mRNA decay. ARE-mRNA turnover was found to be activated by the ubiquitin-addition reaction and blocked by the ubiquitin-removal reaction. Saturation of the ARE-mRNA decay machinery by high levels of ARE-mRNA, which is well established but not understood, was found to be relieved by increased expression of a DUB that promotes ubiquitin addition to proteins. Finally, inhibition of proteasome activity also blocked accelerated ARE-mRNA decay that is mediated by increased ubiquitin recycling. These results demonstrate that both ubiquitinating activity and proteasome activity are essential for rapid turnover of a model cytokine ARE-mRNA containing the GM-CSF ARE.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Actins / metabolism
  • Animals
  • Blotting, Northern
  • COS Cells
  • Cell Line
  • Genes, Reporter
  • Granulocyte-Macrophage Colony-Stimulating Factor / metabolism
  • Models, Biological
  • Plasmids / metabolism
  • Protein Biosynthesis
  • Proto-Oncogene Proteins c-fos / metabolism
  • RNA, Messenger / metabolism*
  • Time Factors
  • Transcription, Genetic
  • Transfection
  • Tumor Necrosis Factor-alpha / metabolism
  • Ubiquitin / chemistry*
  • Ubiquitin / metabolism
  • Up-Regulation

Substances

  • Actins
  • Proto-Oncogene Proteins c-fos
  • RNA, Messenger
  • Tumor Necrosis Factor-alpha
  • Ubiquitin
  • Granulocyte-Macrophage Colony-Stimulating Factor