Nogo-A expression in mouse central nervous system neurons.

The longest central nervous system (CNS) specific isoform of the major myelin-associated inhibitor of neurite growth, Nogo-A, has previously been shown to be expressed largely in oligodendrocytes. Using an antibody raised against a recombinant fusion protein comprising amino acids 223-399 of Nogo-A, we show in this report that Nogo-A is also expressed in the cell body of a distinct set of CNS neurons. The antibody detects a single protein band of 220 kDa in rat brain lysate and neuroblastoma cell lysates. Immunofluorescent analyses reveal that Nogo-A is found largely in the endoplasmic reticulum of neuroblastoma cell lines SH-SY5Y and NIE-115. In the mouse CNS, Nogo-A can be found in specific subsets of neuronal cell bodies in addition to oligodendrocytes, but not glial fibrillary associated protein positive astrocytes or MAC-1 positive microglia. Our results provide a conclusive demonstration of the expression of Nogo-A in CNS neurons, which suggests that Nogo-A may have distinct endogenous roles in neurons other than its known ability to inhibit neurite growth.