- Model for the study of respiratory system and potential treatments.
FGFR4 knockout: Lung alveoli fail to develop normally in double mutant with FGFR4 and FGFR3 knockouts.
The fibroblast growth factor receptor 4 (fgfr-4) gene was inactivated by targeted disruption and homozygous recombination to study its possible role in lung development. FGFR-4 is expressed in postnatal lung, and FGFR-4 null mice have no obvious abnormalities. However, mice that are doubly homozygous for targeted disruptions of FGFR3 and FGFR4 display novel phenotypes, including pronounced dwarfism and lung abnormalities. The lungs of the double knockout mice are normal at birth, but they fail to develop secondary septae that delimit alveoli and increase the surface area of the lung. Although lung function is impaired, the double homozygous knockout mice are viable but sickly.