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Identification of the cystic fibrosis gene: cloning and characterization of complementary DNA
J R Riordan1, J M Rommens, B Kerem
1Department of Biochemistry, Hospital for Sick Children, Toronto, Ontario, Canada.
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.
Insights
Researchers identified a gene linked to cystic fibrosis (CF) on chromosome 7. A specific protein deletion in this gene was found in CF patients, offering insights into the disease mechanism.
Area of Science:
- Molecular Biology
- Genetics
- Cell Biology
Background:
- Cystic Fibrosis (CF) is a genetic disorder affecting epithelial cells.
- The genetic locus for CF was previously mapped to chromosome 7.
- Understanding the molecular basis of CF is crucial for developing effective treatments.
Purpose of the Study:
- To identify and characterize the gene responsible for Cystic Fibrosis.
- To elucidate the structure and function of the protein encoded by the CF gene.
- To investigate the molecular defect leading to CF in affected individuals.
Main Methods:
- Isolation of complementary DNA (cDNA) clones from epithelial cell libraries.
- Screening of genomic DNA segments containing the putative CF locus.
- Analysis of transcript size and tissue distribution.
- Prediction of protein structure and functional domains.
- Detection of specific DNA deletions in CF patients.
Main Results:
- Overlapping cDNA clones were successfully isolated using a genomic DNA probe from chromosome 7.
- Transcripts of approximately 6500 nucleotides were detected in tissues affected by CF.
- The predicted protein features two similar motifs, each with membrane-association and ATP-binding domains.
- A three-base pair deletion, causing phenylalanine omission in the nucleotide-binding domain, was identified in CF patients.
Conclusions:
- The identified gene and its encoded protein are strongly associated with Cystic Fibrosis.
- The protein's predicted domains suggest a role in ion transport or cellular regulation.
- The specific phenylalanine deletion appears to be a key molecular defect underlying CF pathogenesis.