ANTIGENIC COMPARTMENTATION IN THE MOUSE CEREBELLAR CORTEX - ZEBRIN AND HNK-1 REVEAL A COMPLEX, OVERLAPPING MOLECULAR TOPOGRAPHY

Two monoclonal antibodies-anti-zebrin I and anti-HNK-1-have been used to study the compartmentation of the mouse cerebellar cortex. As in ot her species, the pattern of localization of the Purkinje cell specific antigen zebrin I is confined to a subset of Purkinje cells that are o rganized into parasagittal bands. The basic pattern consists of two ab utting paramedian bands (P1+) and up to three additional vermal bands on either side (P2+-P4+). This pattern is altered in the vermal region s of lobules X and VI-VII where all Purkinje cells are immunoreactive. In the hemisphere there are three additional bands present (P5+-P7+) plus two shorter bands in the paravermal area (P4b+ and P5a+) that ext end from the paramedian lobule through the lobulus simplex. This patte rn is very similar, but perhaps not identical, to that previously desc ribed for the rat. These results suggest a common mammalian plan for t he expression and localization of zebrin I. By using a monoclonal anti body to an epitope associated with HNK-1, we have now identified a nov el pattern of compartmentation in mouse cerebellum. The HNK-1 epitope is expressed most notably on Purkinje cells and Golgi cells. The molec ular layer immunoreactivity associated with the Purkinje cell dendrite s varies in intensity in a systematic and reproducible fashion. This r eveals a novel cerebellar compartmentation that is sometimes complemen tary, sometimes overlapping, to that revealed by anti-zebrin. As a res ult, it is now possible to subdivide the cerebellar cortex into a stil l finer mosaic of antigenic patches and bands than was possible by usi ng zebrins alone. (C) 1993 Wiley-Liss, Inc.