CEREBELLAR DEFECT AND IMPAIRED MOTOR COORDINATION IN MICE LACKING VIMENTIN

Vimentin belongs to the family of intermediate filament (IF) proteins. During the nervous system development in mammals, it is transiently e xpressed in precursor cells of neuronal and glial lineages, and then i t is progressively replaced by other types of IF proteins. Surprisingl y, mice knock-out for vimentin develop and reproduce without any appar ent defects (Colucci-Guyon et al. Cell 79:679-694, 1994). In adult rod ents, Bergmann glia (BG) of the cerebellum continue to express vimenti n together with glial fibrillary acidic protein (GFAP). A careful anal ysis of cerebellar morphology and ultrastructure in mutants showed poo rly developed and highly abnormal BG, whereas the migration of granula r neurons proceeded normally. Moreover; many Purkinje cells (PC) appea red stunted with a loss of spiny branchlets, and some of them were nec rotic. Finally, impaired motor coordination was evidenced by behaviora l tests. These observations demonstrate a role for vimentin in contrib uting to the normal development and morphology of BG and reveal a hith erto unreported functional relationship between BG and PC. (C) 1999 Wi ley-Liss, Inc.