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Identification of nucleolin as an AU-rich element binding protein involved in bcl-2 mRNA stabilization

Tapas K Sengupta1, Sumita Bandyopadhyay, Daniel J Fernandes

  • 1Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina 29425, USA.

The Journal of Biological Chemistry
|December 18, 2003
PubMed

Insights

Nucleolin stabilizes BCL2 mRNA by binding to its AU-rich element (ARE). Taxol and okadaic acid treatments degrade nucleolin, leading to BCL2 mRNA destabilization and apoptosis in HL-60 cells.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Cancer Research

Background:

  • BCL2 mRNA stability is regulated by AU-rich elements (AREs).
  • Drug-induced BCL2 mRNA destabilization involves decreased ARE-binding factors.

Purpose of the Study:

  • Identify proteins binding to the BCL2 ARE.
  • Investigate the role of these proteins in BCL2 mRNA regulation and apoptosis.

Main Methods:

  • Affinity purification of BCL2 ARE-binding proteins from HL-60 cells.
  • Mass spectrometry for protein identification.
  • RNA gel shift assays with recombinant nucleolin.
  • mRNA decay assays in cell extracts.
  • Analysis of nucleolin and BCL2 mRNA levels after drug treatment.

Main Results:

  • Nucleolin and its fragments were identified as BCL2 ARE-binding proteins.
  • Recombinant nucleolin specifically binds to the BCL2 ARE and decreases mRNA decay.
  • Taxol and okadaic acid induce nucleolin proteolysis, correlating with BCL2 mRNA down-regulation.

Conclusions:

  • Nucleolin acts as a BCL2 mRNA-stabilizing factor.
  • Drug-induced apoptosis in HL-60 cells involves nucleolin degradation and subsequent BCL2 mRNA destabilization.

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