DIFFERENTIAL DISTRIBUTION OF TAU-PROTEINS IN DEVELOPING CAT CEREBELLUM

The differential distribution and phosphorylation of tau proteins in c at cerebellum was studied with two well characterized antibodies, TAU- 1 and TAU-2. TAU-1 detects tau proteins in axons, and the epitope in p erikarya and dendrites is masked by phosphorylation. TAU-2 detects a p hosphorylation-independent epitope on tau proteins. The molecular comp osition of tau proteins in the range of 45 kD to 64 kD at birth change d after the first postnatal month to a set of several adult variants o f higher molecular weights in the range of 59 kD to 95 kD. The appeara nce of tau proteins in subsets of axons corresponds to the axonal matu ration of cerebellar local-circuit neurons in granular and molecular l ayers and confirms previous studies. Tau proteins were also identified in synapses by immunofluorescent double-staining with synapsin I, loc ated in the pinceau around the Purkinje cells, and in glomeruli. Depho sphorylation of juvenile cerebellar tissue by alkaline phosphatase ind icated indirectly the presence of differentially phosphorylated tau fo rms mainly in juvenile ages. Additional TAU-1 immunoreactivity was unm asked in numerous perikarya and dendrites of stellate cells, and in ce ll bodies of granule cells. Purkinje cell bodies were stained transien tly at juvenile ages. During postnatal development, the intensity of t he phosphate-dependent staining decreased, suggesting that phosphoryla tion of tau proteins in perikarya and dendrites may be essential for e arly steps in neuronal morphogenesis during cat cerebellum development .