A 32-Kilodalton Protein Binds to AU-Rich Domains in the 3′ Untranslated Regions of Rapidly Degraded mRNAs

Evangelia Vakalopoulou, Jerome Schaack, Thomas Shenk

Research output: Contribution to journalArticlepeer-review

254 Scopus citations


An AU-rich sequence present within the 3′ untranslated region has been shown to mark some short-lived mRNAs for rapid degradation. We demonstrate by label transfer and gel shift experiments that a 32-kDa polypeptide, present in nuclear extracts, specifically interacts with the AU-rich domains present within the 3′ untranslated regions of human granulocyte-macrophage colony-stimulating factor, c-fos, and c-myc mRNAs and a similar domain downstream of the poly(A) addition site of the adenovirus IVa2 mRNA. Competition experiments and partial protease analysis indicated that the same polypeptide interacts with all four RNAs. A single AUUUA sequence in a U-rich context was sufficient to signal binding of the 32-kDa polypeptide. Insertion of three copies of this minimal recognition site led to markedly reduced accumulation of β-globin RNA, while the same insert carrying a series of U-to-G changes had little effect on RNA levels. Steady-state levels of β-globin-specific nuclear RNA, including incompletely processed RNA, and cytoplasmic mRNA were reduced. Cytoplasmic mRNA containing the AU-rich recognition sites for the 32-kDa polypeptide exhibited a half-life shorter than that of mRNA with a mutated insert. We suggest that binding of the 32-kDa polypeptide may be involved in the regulation of mRNA half-life.

Original languageEnglish (US)
Pages (from-to)3355-3364
Number of pages10
JournalMolecular and cellular biology
Issue number6
StatePublished - Jun 1991

All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Cell Biology


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