Expression of pp60c-src in adult and developing rat central nervous system.

Brains of adult and fetal (E13-E19) rats were assayed by region for the presence of the proto-oncogene product pp60c-src. pp60c-src was abundant in the adult brain with the highest levels found in the cerebral hemispheres and localized to the cortical cellular layers. In the embryonic nervous system the levels of pp60c-src activity were much higher throughout the brain than those observed in the adult. The expression of pp60c-src was developmentally regulated, but demonstrated a regionally distinct pattern of expression. In the cortex src activity steadily rose during gestation, while in the basal forebrain and midbrain maximal activity was observed at E17 which then declined to adult levels. The data demonstrate that pp60c-src is differentially expressed in regions of the brain, both during development and in the adult.