Posttranscriptional regulation of acute phase serum amyloid A2 expression by the 5'- and 3'-untranslated regions of its mRNA

J Immunol. 1999 Oct 15;163(8):4537-45.

Abstract

Human acute-phase serum amyloid A protein (A-SAA) is a major acute phase reactant, the concentration of which increases dramatically as part of the body's early response to inflammation. A-SAA is the product of two almost identical genes, SAA1 and SAA2, which are induced by the pro-inflammatory cytokines, IL-1 and IL-6. In this study, we examine the roles played by the 5'- and 3'-untranslated regions (UTRs) of the SAA2 mRNA in regulating A-SAA2 expression. SAA2 promoter-driven luciferase reporter gene constructs carrying the SAA2 5'-UTR and/or 3'-UTR were transiently transfected into the HepG2 human hepatoma cell line. After induction of chimeric mRNA with IL-1beta and IL-6, the SAA2 5'- and 3'-UTRs were both able to posttranscriptionally modify the expression of the luciferase reporter. The SAA2 5'-UTR promotes efficient translation of the chimeric luciferase transcripts, whereas the SAA2 3'-UTR shares this property and also significantly accelerates the rate of reporter mRNA degradation. Our data strongly suggest that the SAA2 5'- and 3'-UTRs each play significant independent roles in the posttranscriptional regulation of A-SAA2 protein synthesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3' Untranslated Regions / genetics*
  • 5' Untranslated Regions / genetics*
  • Acute-Phase Proteins / biosynthesis*
  • Acute-Phase Proteins / genetics
  • Enzyme Activation / genetics
  • Gene Expression Regulation / genetics*
  • Genes, Reporter
  • Genetic Vectors / genetics
  • Humans
  • Luciferases / genetics
  • Luciferases / metabolism
  • Promoter Regions, Genetic / genetics
  • RNA Processing, Post-Transcriptional*
  • RNA, Messenger / biosynthesis*
  • RNA, Messenger / genetics
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Serum Amyloid A Protein / biosynthesis*
  • Serum Amyloid A Protein / genetics
  • Tumor Cells, Cultured
  • beta-Galactosidase / genetics

Substances

  • 3' Untranslated Regions
  • 5' Untranslated Regions
  • Acute-Phase Proteins
  • RNA, Messenger
  • Recombinant Fusion Proteins
  • SAA2 protein, human
  • Serum Amyloid A Protein
  • Luciferases
  • beta-Galactosidase