Fig. 1. Analysis of activity of protease in lungs of Egfr^-/- mice by in situ zymography. Cryostat sections of lungs from newborn wildtype (a,c,d) and Egfr^-/- (b) after 3 hours of incubation with DQ gelatin. (a) Note gelatinolytic activity throughout the parenchyma and around the airway of wild-type lung (arrowhead), (d) which was inhibited in the presence of 1,10-phenanthroline. (c) Corresponding phase-contrast image from a.