LOCALIZATION OF UROKINASE-TYPE PLASMINOGEN-ACTIVATOR MESSENGER-RNA INTHE ADULT-MOUSE BRAIN

Urokinase-type plasminogen activator (uPA) is an inducible serine prot ease, secreted by a variety of cell types, that functions in fibrinoly sis and has been implicated also in events such as cell migration and tissue remodeling and repair. To explore the role of uPA in the adult brain, we have now screened the whole mouse brain for cells expressing the uPA gene through in situ hybridization using S-35-complementary R NA. uPA mRNA was visualized predominantly in three regions: (1) the su bicular complex, (2) the entorhinal cortex, (3) the parietal cortex, w here the signal was somewhat lower and confined to layers IV and VI. W eaker signals were seen in the basolateral nucleus of the amygdala and in the anterodorsal thalamic nucleus, and also in the hilus of the de ntate gyrus where labeling was slightly over background. Cells exhibit ing uPA mRNA signaling were large neurons according to morphological c riteria. These results support the view of uPA being involved in neuro nal functions of the adult brain, specifically in the hippocampal form ation and the parietal cortex.