Developmental studies with the 14-3-2 antigen and the neuron specific enolase (NSE) associated activities-I

We have compared the rodent developmental pattern of the 14-3-2 antigen estimated by a microcomplement fixation technique with that of the cerebral enolases. Chromatographic separation of enolase isozymes on microcolumns demonstrates that the embryonic neuron specific enolase is firstly and mostly represented by the ?? isozyme. The most important increase in 14-3-2 antigen and ?? enolase occurs between post-natal days 7th and 15th. By post-natal day 30, adult levels have been reached. An interesting observation is-during embryonic development-the decrease in the specific activity of the cerebral enolase isozyme ??. This could be explained by the replacement-in neuroblasts-of ?? enolase by neuron specific enolase. A comparison between 14-3-2 antigen and neuron specific enolase (??) purified by completely different methods is presented. The 14-3-2 antigen exhibits an enolase specific activity comparable to that of purified enzyme and has the same electrophoretic mobility. Antibodies raised against either antigen have an identical specificity. Pre and post-natal developmental pattern in rodent brains are similar for both proteins. Thus neuron specific 14-3-2 antigen is identical to neuron specific enolase. Thus we have precisely described the ontogenic transition between the three cerebral enolase isozymes at the tissue level. This study is completed by the analysis of these transitions at the neuronal cell level, using homogenous cell lines (Part II of this paper).