Nonsense-mediated mRNA decay affects nonsense transcript levels and governs response of cystic fibrosis patients to gentamicin

J Clin Invest. 2007 Mar;117(3):683-92. doi: 10.1172/JCI28523. Epub 2007 Feb 8.

Abstract

Aminoglycosides can readthrough premature termination codons (PTCs), permitting translation of full-length proteins. Previously we have found variable efficiency of readthrough in response to the aminoglycoside gentamicin among cystic fibrosis (CF) patients, all carrying the W1282X nonsense mutation. Here we demonstrate that there are patients in whom the level of CF transmembrane conductance regulator (CFTR) nonsense transcripts is markedly reduced, while in others it is significantly higher. Response to gentamicin was found only in patients with the higher level. We further investigated the possibility that the nonsense-mediated mRNA decay (NMD) might vary among cells and hence governs the level of nonsense transcripts available for readthrough. Our results demonstrate differences in NMD efficiency of CFTR transcripts carrying the W1282X mutation among different epithelial cell lines derived from the same tissue. Variability was also found for 5 physiologic NMD substrates, RPL3, SC35 1.6 kb, SC35 1.7 kb, ASNS, and CARS. Importantly, our results demonstrate the existence of cells in which NMD of all transcripts was efficient and others in which the NMD was less efficient. Downregulation of NMD in cells carrying the W1282X mutation increased the level of CFTR nonsense transcripts and enhanced the CFTR chloride channel activity in response to gentamicin. Together our results suggest that the efficiency of NMD might vary and hence have an important role in governing the response to treatments aiming to promote readthrough of PTCs in many genetic diseases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aminoglycosides / therapeutic use*
  • Anti-Bacterial Agents / therapeutic use*
  • Codon, Nonsense / genetics*
  • Cystic Fibrosis / drug therapy*
  • Cystic Fibrosis / genetics
  • Cystic Fibrosis Transmembrane Conductance Regulator / genetics*
  • Cystic Fibrosis Transmembrane Conductance Regulator / metabolism
  • Drug Resistance / genetics
  • Gentamicins / therapeutic use*
  • Humans
  • Mutation
  • RNA Stability / genetics*
  • RNA, Messenger / metabolism
  • Transcription, Genetic

Substances

  • Aminoglycosides
  • Anti-Bacterial Agents
  • Codon, Nonsense
  • Gentamicins
  • RNA, Messenger
  • Cystic Fibrosis Transmembrane Conductance Regulator