A COMPARATIVE-STUDY OF THE DISTRIBUTION OF ALPHA-ENOLASE AND GAMMA-ENOLASE SUBUNITS IN CULTURED RAT NEURAL CELLS AND FIBROBLASTS

We report the presence and distribution of alpha (ubiquitous) and gamm a (neuron-specific) subunits of the dimeric glycolytic enzyme enolase (2-phospho-D-glycerate hydrolase) in cultured neural cells. The gy eno lase is found in vivo at high levels only in neurons and neuroendocrin e cells. Neuronal cells in culture also contain relatively high levels of alpha gamma and gamma gamma enolase. Here we show, by enzymatic an d immunological techniques, that the gamma subunit also is expressed i n cultured rat astrocytes and meningeal fibroblasts and, as we previou sly reported, in oligodendrocytes. Both neuron-specific isoforms alpha gamma and gamma gamma are expressed in all these cells, but the alpha alpha isoform accounts for the major part of total enolase activity. The sum of alpha gamma and gamma gamma enolase activities increases wi th time in culture, i.e. maturation processes, reaching the highest le vel in oligodendroytes (40% of total enolase activity) and 15 and 10% of total enzymatic activity in astrocytes and fibroblasts, respectivel y. The gamma enolase transcripts were found not only in cultured neuro nal cells but also in cultured oligodendrocytes, astrocytes, and menin geal fibroblasts. Our data indicate that neuron-specific enolase shoul d be used with caution as a specific marker for neuronal cell differen tiation. (C) 1997 ISDN.