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  • The EMBO Journal (2002) 21, 4709 - 4718
  • doi:10.1093/emboj/cdf444

  • Subject Category:

Functional cloning of BRF1, a regulator of ARE-dependent mRNA turnover

Georg Stoecklin1,2, Marco Colombi1, Ines Raineri1, Sabrina Leuenberger1, Michel Mallaun1, Martin Schmidlin1, Brigitte Gross1, Min Lu1, Toshio Kitamura3 and Christoph Moroni1

  1. Institute of Medical Microbiology, University of Basel, Petersplatz 10, 4003 Basel, Switzerland
  2. Present address: Division of Rheumatology and Immunology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
  3. Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan

Correspondence to:

Christoph Moroni, E-mail: Christoph.Moroni@unibas.ch

Received 3 December 2001; Accepted 5 July 2002; Revised 8 May 2002

To identify regulators of AU-rich element (ARE)-dependent mRNA turnover we have followed a genetic approach using a mutagenized cell line (slowC) that fails to degrade cytokine mRNA. Accordingly, a GFP reporter construct whose mRNA is under control of the ARE from interleukin-3 gives an increased fluorescence signal in slowC. Here we describe rescue of slowC by a retroviral cDNA library. Flow cytometry allowed us to isolate revertants with reconstituted rapid mRNA decay. The cDNA was identified as butyrate response factor-1 (BRF1), encoding a zinc finger protein homologous to tristetraprolin. Mutant slowC carries frame-shift mutations in both BRF1 alleles, whereas slowB with intermediate decay kinetics is heterozygous. By use of small interfering (si)RNA, independent evidence for an active role of BRF1 in mRNA degradation was obtained. In transiently transfected NIH 3T3 cells, BRF1 accelerated mRNA decay and antagonized the stabilizing effect of PI3-kinase, while mutation of the zinc fingers abolished both function and ARE-binding activity. This approach, which identified BRF1 as an essential regulator of ARE-dependent mRNA decay, should also be applicable to other cis-elements of mRNA turnover.

  • Keywords:

    • AU-rich element,
    • ERF-1,
    • mRNA stability,
    • siRNA,
    • zinc finger protein