The Spontaneous Ataxic Mouse Mutant Tippy is Characterized by a Novel Purkinje Cell Morphogenesis and Degeneration Phenotype

Evelyn K. Shih, Gabriella Sekerková, Gen Ohtsuki, Kimberly A. Aldinger, Viktor Chizhikov, Christian Hansel, Enrico Mugnaini, Kathleen J. Millen

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

This study represents the first detailed analysis of the spontaneous neurological mouse mutant, tippy, uncovering its unique cerebellar phenotype. Homozygous tippy mutant mice are small, ataxic, and die around weaning. Although the cerebellum shows grossly normal foliation, tippy mutants display a complex cerebellar Purkinje cell phenotype consisting of abnormal dendritic branching with immature spine features and patchy, non-apoptotic cell death that is associated with widespread dystrophy and degeneration of the Purkinje cell axons throughout the white matter, the cerebellar nuclei, and the vestibular nuclei. Moderate anatomical abnormalities of climbing fiber innervation of tippy mutant Purkinje cells were not associated with changes in climbing fiber-EPSC amplitudes. However, decreased ESPC amplitudes were observed in response to parallel fiber stimulation and correlated well with anatomical evidence for patchy dark cell degeneration of Purkinje cell dendrites in the molecular layer. The data suggest that the Purkinje neurons are a primary target of the tippy mutation. Furthermore, we hypothesize that the Purkinje cell axonal pathology together with disruptions in the balance of climbing fiber and parallel fiber-Purkinje cell input in the cerebellar cortex underlie the ataxic phenotype in these mice. The constellation of Purkinje cell dendritic malformation and degeneration phenotypes in tippy mutants is unique and has not been reported in any other neurologic mutant. Fine mapping of the tippy mutation to a 2.1 MB region of distal chromosome 9, which does not encompass any gene previously implicated in cerebellar development or neuronal degeneration, confirms that the tippy mutation identifies novel biology and gene function.

Original languageEnglish (US)
Article number640
Pages (from-to)292-307
Number of pages16
JournalCerebellum
Volume14
Issue number3
DOIs
StatePublished - Jun 26 2015

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Purkinje Cells
Morphogenesis
Phenotype
Mutation
Neurologic Mutant Mice
Vestibular Nuclei
Cerebellar Nuclei
Chromosomes, Human, Pair 9
Cerebellar Cortex
Dendrites
Weaning
Cerebellum
Nervous System
Genes
Axons
Spine
Cell Death
Pathology

All Science Journal Classification (ASJC) codes

  • Neurology
  • Clinical Neurology

Cite this

The Spontaneous Ataxic Mouse Mutant Tippy is Characterized by a Novel Purkinje Cell Morphogenesis and Degeneration Phenotype. / Shih, Evelyn K.; Sekerková, Gabriella; Ohtsuki, Gen; Aldinger, Kimberly A.; Chizhikov, Viktor; Hansel, Christian; Mugnaini, Enrico; Millen, Kathleen J.

In: Cerebellum, Vol. 14, No. 3, 640, 26.06.2015, p. 292-307.

Research output: Contribution to journalArticle

Shih, EK, Sekerková, G, Ohtsuki, G, Aldinger, KA, Chizhikov, V, Hansel, C, Mugnaini, E & Millen, KJ 2015, 'The Spontaneous Ataxic Mouse Mutant Tippy is Characterized by a Novel Purkinje Cell Morphogenesis and Degeneration Phenotype', Cerebellum, vol. 14, no. 3, 640, pp. 292-307. https://doi.org/10.1007/s12311-014-0640-x
Shih, Evelyn K. ; Sekerková, Gabriella ; Ohtsuki, Gen ; Aldinger, Kimberly A. ; Chizhikov, Viktor ; Hansel, Christian ; Mugnaini, Enrico ; Millen, Kathleen J. / The Spontaneous Ataxic Mouse Mutant Tippy is Characterized by a Novel Purkinje Cell Morphogenesis and Degeneration Phenotype. In: Cerebellum. 2015 ; Vol. 14, No. 3. pp. 292-307.
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