[Cystic fibrosis: a gene at the end of the road]

The authors first give an account of the work undertaken jointly by two Canadian and one American groups, which lead to the cloning and identification of the cystic fibrosis gene. To achieve this aim, it was necessary to clone a large region amounting to 500 kb, using chromosome walking and jumping. The gene was located from a cross-hybridization signal with two probes from the cloned region and bovine cDNA. The CF gene is made of 24 exons giving a messenger of 6,500 nucleotides and a protein of about 1,500 aminoacids. The protein structure has been deduced from its composition in aminoacids. However, the localization of the protein in the cell and its true function remain an open question. At the same time workers from those groups identified the prevalent mutation in CF. These outstanding achievements will help unravelling the physiopathology of the disease. They increase the possibilities of prevention, but it is fanciful to think that they can lead to its eradication.