Journal of Neuroscience, Vol 11, 2295-2302, Copyright © 1991 by Society for Neuroscience
The Lurcher cerebellar mutant phenotype is not expressed on a staggerer mutant background
A Messer, B Eisenberg and J Plummer
Wadsworth Center for Laboratories and Research, New York State Department of Health, Albany 12201-0509.
The hierarchy of the various processes responsible for the development of
the complex, elaborated Purkinje cell can be examined by taking advantage
of a series of spontaneous mutations that affect cerebellar development in
the mouse. This study uses double mutants containing genes for two separate
hereditary cerebellar mutations that have been shown to act intrinsically
in Purkinje cells in order to investigate the time course and modes of
action of these mutations. Lurcher mice show 100% degeneration of Purkinje
cells, starting during the second postnatal week, while staggerer mice show
reduced numbers of Purkinje cells in a distinctive mediolateral
distribution from the time of birth, with the remainder grossly stunted.
When these mutations are combined genetically, mice shown by progeny tests
to harbor both staggerer and Lurcher genotypes exhibit staggerer-like
behavior and overall cerebellar morphology; they also do not lose 100% of
their Purkinje cells, as Lurcher mutants would otherwise do. Instead, they
show a characteristic staggerer cerebellar pathology. We conclude that the
intrinsic action of the staggerer gene in Purkinje cells occurs earlier in
development than do effects of the Lurcher gene, and that the action of the
staggerer gene prevents Purkinje cells from acquiring the characteristics
required for the cytotoxic action of the Lurcher gene.