Regional location of α1-antichymotrypsin and α1-antitrypsin genes on human chromosome 14

Abstract

The human protease inhibitor genes α₁ antitrypsin (α₁-PI) and α₁-antichymotrypsin (α₁-ACT) are acute-phase proteins which are induced in response to inflammation. These inhibitors function to limit the activity of serine proteases in vivo. α₁-PI acts as an inhibitor of neutrophil elastase to protect the elastin fibers of the lung. Genetic deficiencies of α₁-PI result in development of chronic pulmonary emphysema. The physiologic role of α₁-ACT has not been clearly defined, but it also appears to function in the maintenance of protease-protease inhibitor equilibrium in the lung. Nucleic acid and protein sequence homologies detected between α₁-PI and α₁ t-ACT suggested an evolutionary relationship. Gene mapping experiments were performed to determine if these protease inhibitor genes reside at the same chromosomal locus in man. In situ hybridization data demonstrate that both α₁-PI and α₁-ACT map to the same region, q31–q32.3, on chromosome 14.