Identification of the Cystic Fibrosis Gene: Cloning and Characterization of Complementary DNA

Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
Science (Impact Factor: 33.61). 10/1989; 245(4922):1066-73. DOI: 10.1126/science.2475911
Source: PubMed

ABSTRACT Overlapping complementary DNA clones were isolated from epithelial cell libraries with a genomic DNA segment containing a
portion of the putative cystic fibrosis (CF) locus, which is on chromosome 7. Transcripts, approximately 6500 nucleotides
in size, were detectable in the tissues affected in patients with CF. The predicted protein consists of two similar motifs,
each with (i) a domain having properties consistent with membrane association and (ii) a domain believed to be involved in
ATP (adenosine triphosphate) binding. A deletion of three base pairs that results in the omission of a phenylalanine residue
at the center of the first predicted nucleotide-binding domain was detected in CF patients.

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Available from: John R Riordan, Jan 15, 2015
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    • "The correlation between transepithelial fluid transport and mucociliary clearance is demonstrated by cystic fibrosis (CF) lung disease. The devastating disease is caused by mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) [3], a Cl − channel that is ubiquitously expressed at the luminal side of pulmonary epithelial cells [4] [5]. The main function of CFTR is to facilitate Cl − [6] [7] and HCO 3 − [8] [9] secretion. "
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    ABSTRACT: Fluid homeostasis mediated by the airway epithelium is required for proper lung function, and the CFTR (cystic fibrosis transmembrane conductance regulator) Cl(-) channel is crucial for these processes. Luminal acetylcholine (ACh) acts as an auto-/paracrine mediator to activate Cl(-) channels in airway epithelia and evidence exists showing that nicotinic ACh receptors activate CFTR in murine airway epithelia. The present study investigated whether or not luminal ACh regulates CFTR activity in airway epithelia of pigs, an emerging model for investigations of human airway disease and cystic fibrosis (CF) in particular. Transepithelial ion currents of freshly dissected pig tracheal preparations were measured with Ussing chambers. Application of luminal ACh (100μM) induced an increase of the short-circuit current (ISC). The ACh effect was mimicked by muscarine and pilocarpine (100μM each) and was sensitive to muscarinic receptor antagonists (atropine, 4-DAMP, pirenzepine). No changes of the ISC were observed by nicotine (100μM) and ACh responses were not affected by nicotine or mecamylamine (25μM). Luminal application of IBMX (I, 100μM) and forskolin (F, 10μM), increase the ISC and the I/F-induced current were decreased by the CFTR inhibitor GlyH-101 (GlyH, 50μM) indicating increased CFTR activity by I/F. In contrast, GlyH did not affect the ACh-induced current, indicating that the ACh response does not involve the activation of the CFTR. Results from this study suggest that luminal ACh does not regulate the activity of the CFTR in tracheal epithelia of pigs which opposes observation from studies using mice airway epithelium. Copyright © 2015 Elsevier B.V. All rights reserved.
    International immunopharmacology 08/2015; DOI:10.1016/j.intimp.2015.08.010 · 2.47 Impact Factor
    • "Cystic fibrosis (CF) is the most common severe autosomal recessive disease in Caucasians, caused by mutations in the gene (Riordan et al. 1989), that encodes for the CF transmembrane conductance regulator (CFTR) protein, a chloride (Cl À ) channel expressed at the apical membrane of epithelial cells and regulating salt and water transport "
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    ABSTRACT: Cystic fibrosis (CF), the most common recessive autosomal disease among Caucasians, is caused by mutations in the gene encoding the CF transmembrane conductance regulator (CFTR) protein. The most common mutation, F508del, leads to CFTR impaired plasma membrane trafficking. Therapies modulating CFTR basic defect are emerging, such as VX-809, a corrector of F508del-CFTR traffic which just succeeded in a Phase III clinical trial. We recently showed that VX-809 is additive to two other correctors (VRT-325 and compound 4a). Here, we aimed to determine whether the differential rescuing by these compounds results from cell-specific factors or rather from distinct effects at the early biogenesis and/or processing. The rescuing efficiencies of the above three correctors were first compared in different cellular models (primary respiratory cells, cystic fibrosis bronchial epithelial and baby hamster kidney [BHK] cell lines) by functional approaches: micro-Ussing chamber and iodide efflux. Next, biochemical methods (metabolic labeling, pulse-chase and immunoprecipitation) were used to determine their impact on CFTR biogenesis / processing. Functional analyses revealed that VX-809 has the greatest rescuing efficacy and that the relative efficiencies of the three compounds are essentially maintained in all three cellular models tested. Nevertheless, biochemical data show that VX-809 significantly stabilizes F508del-CFTR immature form, an effect that is not observed for C3 nor C4. VX-809 and C3 also significantly increase accumulation of immature CFTR. Our data suggest that VX-809 increases the stability of F508del-CFTR immature form at an early phase of its biogenesis, thus explaining its increased efficacy when inducing its rescue.
    08/2015; 3(4):e00152. DOI:10.1002/prp2.152
    • "Nevertheless, comparison of global gene expression data in related tissues under different conditions might provide valuable insights into the shared pathological pathways and regulatory networks dysregulated in individual diseases. CF, an autosomal recessive genetic disorder caused primarily by mutations in the gene encoding the CF transmembrane conductance regulator (CFTR) protein [43], is characterized by a progressive lung disease brought about by dehydration of the epithelial airway surface liquid (ASL) and a failure of mucociliary clearance, leading to recurrent bacterial infections and a chronic inflammatory response [16]. Some clinical features of CF are shared by obstructive lung diseases such as chronic obstructive pulmonary disorder (COPD: [42]) and asthma [39], with airway surface dehydration [33] and chronic inflammation [3] implicated in the pathology of all three of these disorders. "
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    ABSTRACT: A meta-analysis of 13 independent microarray data sets was performed and gene expression profiles from cystic fibrosis (CF), similar disorders (COPD: chronic obstructive pulmonary disease, IPF: idiopathic pulmonary fibrosis, asthma), environmental conditions (smoking, epithelial injury), related cellular processes (epithelial differentiation/regeneration), and non-respiratory "control" conditions (schizophrenia, dieting), were compared. Similarity among differentially expressed (DE) gene lists was assessed using a permutation test, and a clustergram was constructed, identifying common gene markers. Global gene expression values were standardized using a novel approach, revealing that similarities between independent data sets run deeper than shared DE genes. Correlation of gene expression values identified putative gene regulators of the CF transmembrane conductance regulator (CFTR) gene, of potential therapeutic significance. Our study provides a novel perspective on CF epithelial gene expression in the context of other lung disorders and conditions, and highlights the contribution of differentiation/EMT and injury to gene signatures of respiratory disease. Copyright © 2015. Published by Elsevier Inc.
    Genomics 07/2015; DOI:10.1016/j.ygeno.2015.07.005 · 2.28 Impact Factor
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