DEVELOPMENTALLY-REGULATED AND SPATIALLY RESTRICTED ANTIGENS OF RADIALGLIAL-CELLS

Radial glial cells, present in many parts of the embryonic vertebrate central nervous system (CNS), have been implicated in the guidance of neuroblasts from the ventricular zone to their laminar destinations. M oreover, radial glial cells may be progenitors of some CNS neurons and glia. To gain new insight into the structure and development of these cells, we have generated and characterized a panel of monoclonal anti bodies that recognize radial glial cells of the chick optic tectum. Mi ce were immunized with homogenates of embryonic day (E) 10 tectum, and antibodies were analyzed by immunofluorescence and immunoblotting. We describe here three pairs of antibodies. 1) H5 and a previously gener ated antibody, R5 (Drager et al., J. Neurosci. 4:2025, 1984), stain th e whole extent of the radial glial cell from E7 to E20. In cultures pr epared from E10 tecta, both stain a filamentous meshwork in glial cell s but not in neurons. On immunoblots, both recognize a protein of simi lar to 52 kD that is closely related (or identical) to vimentin. 2) H2 8 and H29 stain radial glia between E7 and E14, but not later. Moreove r, H28 and H29 staining is markedly more intense in the ventricular an d intermediate zones than in the laminae of the tectal plate. Both of these antibodies recognize an intracellular epitope in cultured glial cells and a protein of similar to 35 kD on immunoblots. 3) H2 and H27 recognize antigens concentrated in the most superficial processes and endfeet of radial glia in late (E16-E20) embryos. They stain distinct structures in cultured glia, suggesting that they recognize distinct a ntigens. H27 recognizes a protein of similar to 29 kD on immunoblots. Thus antibodies H5 and R5 are good markers of radial glial cells at al l stages, whereas the others define antigens that are developmentally regulated and localized to discrete domains. Together, these antibodie s can be used to study temporal and spatial specializations of radial glia.