The development of bergmann glia in mutant mice with cerebellar malformations: Reeler, staggerer and weaver. Immunofluorescence study with antibodies to the glial fibrillary acidic protein

The development of Bergmann glia has been studied by immunofluorescence with glial fibrillary acidic (GFA) protein antiserum in three mouse mutants with cerebellar malformations: reeler, staggerer and weaver. In none of these mutants was astrocytic differentiation delayed. The appearance of Bergmann glia in four‐day‐old reeler, staggerer and weaver mice was normal. Abnormalities of the neuroglial framework in the cerebellar cortex were observed later in development. In reeler mice immunofluorescent astrocytic fibers formed a mesh throughout the cerebellum. Radially oriented fibers were not observed. In staggerer mice Bergmann fibers shorter and more irregular than in littermate controls were still observed on the 14th day. Bergmann fibers were no more demonstrated by immunofluorescence in staggerer mice sacrificed later in development and little immunofluorescence was observed anywhere in the cerebellum of these animals. Heterozygous weaver and normal littermates were easily recognized in cryostat sections stained with toluidine blue, but the immunofluorescent pattern of Bergmann fibers was identical throughout development. Bergmann fibers were present and apparently not decreased in number in homozygous weaver mice but they had an immature appearance, i.e., they were shorter, less straight and less evenly spaced than in normal littermates of comparable age. In one‐month‐old homozygous weaver mice a dense mesh of immunofluorescent fibers with the general orientation of Bergmann fibers was present within the molecular layer of the cerebellum.