PURKINJE-CELL COMPARTMENTS IN THE REELER MUTANT MOUSE AS REVEALED BY ZEBRIN-II AND 90-ACETYLATED GLYCOLIPID ANTIGEN EXPRESSION

The cerebellum is organized into a series of parasagittally aligned ba nds that may be revealed histologically in the adult mouse by largely complementary immunostaining of Purkinje cell sets with the monoclonal antibodies Zebrin II (ZII; antigen:aldolase C) and P-path (PP; antige n:90-acetyl glycolipids). We compared the normal staining pattern usin g these markers and an antibody to calbindin with that found in the re eler mutants (rl/rl), in which most Purkinje cell migration is halted beneath the cerebellar white matter. The results revealed that Purkinj e cells in reeler mutants, despite their ectopic location in large sub cortical masses, show a clear tendency to distribute into alternating zones that either stain for Zebrin II or for P-path, with variable tra nsition zones of mixed labeling. However, the estimated number of zone s was fewer than in the normal adult cortex: roughly 7-9 zones are rev ealed per side in the mutant compared with 14 major divisions in wild type mice. These results raise the possibility that neurons destined t o express these markers are segregated during their migration and that the final phase of migration into the cortex might involve further sp litting or interdigitation between cell sets expressing the two antige ns.