Expression of the cystic fibrosis transmembrane conductance regulator gene in the respiratory tract of normal individuals and individuals with cystic fibrosis

Bruce C. Trapnell, Chin Shyan Chu, Paavo K. Paakko, Tyrone C. Banks, Kunihiko Yoshimura, Victor J. Ferrans, Milica S. Chernick, Ronald Crystal

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The most common mutation of the cystic fibrosis transmembrane conductance regulator gene, CFTR, associated with the clinical disorder cystic fibrosis (CF) is called "ΔPhe508," a triple-base deletion resulting in loss of phenyl-alanine at residue 508 of the predicted 1480-amino acid CFTR protein. In the context that the lung is the major site of morbidity and mortality in CF, we evaluated airway epithelial cells for CFTR mRNA transcripts in normal individuals, normal-ΔPhe508 heterozygotes, and ΔPhe508 homozygotes to determine if the normal and ΔPhe508 CFTR alleles are expressed in the respiratory epithelium, to what extent they are expressed, and whether there are relative differences in the expression of the normal and abnormal alleles at the mRNA level. Respiratory tract epithelial cells recovered by fiberoptic bronchoscopy with a cytology brush demonstrated CFTR mRNA transcripts with sequences appropriately reflecting the normal and ΔPhe508 CFTR alleles of the various study groups. CFTR gene expression quantified by limited polymerase chain reaction amplification showed that in normal individuals, CFTR mRNA transcripts are expressed in nasal, tracheal, and bronchial epithelial cells at ≈1-2 copies per cell, more than 100-fold greater than in pharyngeal epithelium. Importantly, allele-specific hybridization studies demonstrated that the normal and ΔPhe508 CFTR alleles are expressed in the respiratory epithelium in similar amounts.

Original languageEnglish
Pages (from-to)6565-6569
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number15
Publication statusPublished - 1 Aug 1991
Externally publishedYes



  • Epithelial cells
  • mRNA
  • Quantitative polymerase chain reaction

ASJC Scopus subject areas

  • General

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