Characterization and distribution of a new cell surface marker of neuronalprecursors

In a screen for novel cell surface markers of neuronal progenitors, we rece ntly identified mAb 2F7 that recognizes an epitope present on both progenit or cells and postmitotic neurons, in the developing CNS and PNS. In the emb ryonic rat telencephalon, the mAb 2F7 epitope is expressed by migratory and postmigratory neurons in the developing cerebral cortex, as well as by pre sumptive neuronal progenitor cells of the ventricular zone. In the neonatal forebrain mAb 2F7 labels postmitotic neurons, including those of the devel oping cerebral cortex and olfactory bulb, as well as the axons of the corpu s callosum. While mAb 2F7 immunoreactivity is present on only a low density of the neuronal progenitor cells situated in the anterior part of the subv entricular zone, a progressively higher proportion of cells forming the ros tral migratory stream express this epitope. mAb 2F7 labels the surfaces of neurons and neuronal precursors, but not mature oligodendrocytes and astroc ytes in primary cultures derived from the rat neural tube. In vivo, migrati ng neural crest cells, motor neurons, and axonal projections associated wit h the spinal cord express the mAb 2F7 epitope. Immunoblot analyses reveal t hat the mAb 2F7 epitope resides on several high-molecular-weight, membrane- associated proteins, and is likely to be composed of N-linked carbohydrate. These findings suggest that mAb 2F7 recognizes a novel epitope that is pre sent on progenitor cells and postmitotic, differentiating neurons in the de veloping mammalian nervous system. Copyright (C) 2000 S. Karger AG, Basel.