Two proteins associated with cerebellar hypoplasia in jaundiced Gunn rats

Two cerebellar proteins with apparent molecular weights of 250,000 (GR-250) and 50,000 (GR-50) are closely associated with cerebellar hypoplasia in jaundiced homozygous Gunn rats. These proteins, found in Gunn rat cerebellum (4-60 days of age) and cerebrum as well as staggerer mouse cerebellum, were studied with electrophoretic techniques. After 8 days of life, GR-250 decreased and GR-50 increased in the homozygous Gunn rat cerebellum. The pI's of GR-250 and GR-50 were 4.7-5.8 and 4.6-4.9, respectively, and the former protein was shown to bind to Concanavalin A. A comparative study between cerebella of Gunn rats and staggerer mice revealed that GR-250 and P400, a protein generally thought to be characteristic of the Purkinje cells, were identical. Evidence was also obtained showing that GR-250 was present in the Gunn rat cerebrum. GR-50 was not detectable in the staggerer mouse cerebellum but instead, a protein (MW 47,000) was found to be increased in the mutant mouse cerebellum.