These mice carry a spontaneous recessive mutation at the nr locus characterized by a ruffled and disheveled appearance, are slightly smaller than their affected littermates, and exhibit ataxia.Read More +
On the BALB/cByJ background nervous homozygotes have a delayed expression of the mutant phenotype relative to that on the C3HeB/FeJ background (see Stock No. 000229). At 8 to 9 weeks of age homozygotes have a ruffled and disheveled appearance and are slightly smaller than their affected littermates. They are ataxic, having an unsteady gait particularly in the hindquarters, but do not display tremors. They are more active than their littermates. Males and females are affected equally and have a normal lifespan. These mice are good breeders with few non-productive matings. A cross between C3Fe.CGr(Cg)-nr/J homozygotes and BALB/cByJ-nr/J homozygotes produced compound heterozygotes most of which presented with the nervous phenotype by 4 weeks of age, although some had onset delayed as much as to 7 weeks of age (Giggey and Thompson, 2005).
There is a 90% loss of Purkinje cells between 23 and 50 days in homozygous mutant mice. The mitochondria of all Purkinje cells become large and rounded beginning at 9 days. Subsequently most Purkinje cells degenerate. In the retina there is degeneration of the photoreceptors, which is already present at 13 days. The nearly total lack of Purkinje cells in nervous mice has been used as a tool in several investigations of the chemistry, physiology, and development of these cells.