CFTR gene

Cystic fibrosis (CF) is caused by mutations in the CF transmembrane conductance regulator (CFTR), a chloride (CF) channel characterised by chloride permeability and secretion, and also by the regulation of other epithelial ion channels (Eidelman et al, 2001). Mutations in the CFTR gene lead to an impaired or absent Cl conductance in the epithelial apical membrane, which leads to defective Cl secretion and absorption across the epithelium. Genistein (Illek et al, 1995 Weinreich et al, 1997) and other flavonoids (Illek and Fisher, 1998) have been shown, in different animal and tissue models, to activate wild-type CFTR and CFTR mutants by (Eidelman et al, 2001 Roomans, 2001 Suaud et al, 2002) ... 

Caplen NJ, Alton EW, Middleton PG, Dorin JR, Stevenson BJ, Gao X, Durham SR, Jeffery PK, Hodson ME, Coutelle C (1995) Liposome-mediated CFTR gene transfer to the nasal epithelium of patients with cystic fibrosis. Nat Med 1 39-46... 

Ziady AG, Kelley TJ, Milliken E, Ferkol T, Davis PB (2002) Functional evidence of CFTR gene transfer in nasal epithelium of cystic fibrosis mice in vivo following luminal application of DNA complexes targeted to the serpin-enzyme complex receptor. Mol Ther 5 413-419... 

The cystic fibrosis (cf) gene was first identified in 1989. It codes for CFTR, a 170 kDa protein that serves as a chloride channel in epithelial cells. Inheritance of a mutant cftr gene from both parents results in the cystic fibrosis phenotype. While various organs are affected, the most severely affected are the respiratory epithelial cells. These cells have, unsurprisingly, become the... 

The CFTR gene is located on the long arm of chromosome 7 at position 7q31.2. 

Kammouni, W., B. Moreau, F. Becq, A. Saleh, A. Pavirani, C. Figarella, and M. D. Merten. 1999. A cystic fibrosis tracheal gland cell line, CF-KM4. Correction by adenovirus-mediated CFTR gene transfer. Am J Respir Cell Mol Biol 20(4) 684—91. 

Alton EW, Stern M, Farley R, et al. Cationic lipid-mediated CFTR gene transfer to the lungs and nose of patients with cystic fibrosis a double-blind placebo-con-trolled trial. Lancet 1999 353(9157) 947-954. 

Several vectors have been used in an attempt to deliver the cf gene to the airway epithelial cells of sufferers. The most notable systems include adenoviruses and cationic liposomes. Vector delivery to the target cells can be achieved directly by aerosol technology. Delivery of cftr cDNA to airway epithelial cells (and subsequent gene expression) has been demonstrated with the use of both vector types. However, in order to be of therapeutic benefit, it is essential that 5-10% of the target cell population receive and express the cftr gene. This level of integration has not been... 

Answer Aerosol delivery of the CFTR gene. Both viruses and liposome-DNA complexes are capable of successful CFTR gene transfer to the nasal and airway epithelia of patients with CF. In fact, gene transfer to the airways is one of the few areas where liposome-DNA complexes match the expression obtained using viral vectors without the viruses inflammatory side effects. Current trials are aimed at optimizing gene delivery with reduced toxicity to produce sustained correction of the epithelial transport defect. 

To take a step closer to defining the function of DNA sequences, the sequences are fluorescence tagged to identify transcriptional activity of genes (but not translation of protein), which then can be related to the disease state or medication. This information allows researchers to hunt for genes that are affected in disease states (e.g., mutation in CFTR gene regulating a chloride channel in cystic fibrosis patients)... 

Mutant CFTR gene Is missing three bases (PCR gives a shorter than normal product)... 

Heterozygote has both a normal and a mutant allelle of the CFTR gene and PCR produces two products. 

Children with cystic fibrosis lose excessive amounts of salt in perspiration and become dehydrated readily. A salty taste of the skin and an elevated chloride concentration of sweat are traditional diagnostic symptoms.3 More serious problems arise from progressive respiratory failure and inadequate pancreatic secretion. Lung infections with Pseudomonas aeruginosa are the major cause of death. The CFTR gene is expressed in many tissues, especially those of the mucous membranes. 

Genetic researchers successfully transferred the CFTR (cystic fibrosis transraembrane conductance regulator) gene into the intestines of mice. Tliis appeared to be a major step towards gene therapy for patients with cystic fibrosis. Rese arc Iters reported early success with a liposomal method for delivering the CFTR gene in humans. 

A systematic analysis to determine the biophysical characteristics of some cationic lipid/DNA complexes from this series was undertaken (Eastman et al., 1997). Product 1 (Figure 15.7) is currently being used in clinical trials as a carrier of CFTR gene in cystic fibrosis. The synthesis of these cholesteryl derivatives is similar to that of DC-Chol cholesteryl chloroformate is reacted with spermine or spermidine as polycation (Lee et al., 1996). 

Walsh, S. M., Flotte, T. R., Beck, S., et al. Delivery of CFTR gene to rabbit airways by gelatin-DNA microsphere. Int. Symp. Control. Rel. Bioact. Mater, 23 73-74, 1996. 

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