Abstract
1. In the present investigation we demonstrate the occurrence and immunocytochemical localization of 2′,3′-cyclic nucleotide 3′-phosphodiesterase (CNPase; EC 3.1.4.37) in primary nerve cell cultures from rat brain. 2. Using a specific antiserum to purified CNPase the enzyme has been detected by immunofluorescence staining on the cell surface as well as within the cell body and processes of oligodendrocytes. 3. Substantial amounts of CNPase activity are expressed in these cells prior to the onset of myelin formation. 4. The enzyme activity rapidly increases severalfold in culture during developmental stages corresponding to the period around birth. 5. In contrast to neuronal tumor cell lines [Müller, H. W.,et al. (1981).J. Neurochem. 37:947–955; Müller, H. W., and Seifert, W. (1982).Cell. Mol. Neurobiol. 2:227–239], primary neurons from rat brain do not synthesize the enzyme.