Suppression of calbindin-D28k expression exacerbates SCA1 phenotype in a disease mouse model

Cerebellum. 2012 Sep;11(3):718-32. doi: 10.1007/s12311-011-0323-9.


Spinocerebellar ataxia type 1 (SCA1) is an autosomal dominant neurological disorder caused by the expansion of a polyglutamine tract in the mutant protein ataxin-1. The cerebellar Purkinje cells (PCs) are the major targets of mutant ataxin-1. The mechanism of PC death in SCA1 is not known; however, previous work indicates that downregulation of specific proteins involved in calcium homeostasis and signaling by mutant ataxin-1 is the probable cause of PC degeneration in SCA1. In this study, we explored if targeted deprivation of PC specific calcium-binding protein calbindin-D28k (CaB) exacerbates ataxin-1 mediated toxicity in SCA1 transgenic (Tg) mice. Using behavioral tests, we found that though both SCA1/+ and SCA1/+: CaB null (-/+) double mutants exhibited progressive impaired performance on the rotating rod, a simultaneous enhancement of exploratory activity, and absence of deficits in coordination, the double mutants were more severely impaired than SCA1/+ mice. With increasing age, SCA1/+ mice showed a progressive loss in the expression and localization of CaB and other PC specific calcium-binding and signaling proteins. In double mutants, these changes were more pronounced and had an earlier onset. Gene expression profiling of young mice exhibiting no behavior or biochemical deficits revealed a differential expression of many genes common to SCA1/+ and CaB-/+ lines, and unique to SCA1/+: CaB-/+ phenotype. Our study provides further evidence for a critical role of CaB in SCA1 pathogenesis, which may help identify new therapeutic targets to treat SCA1 or other cerebellar ataxias.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Ataxin-1
  • Ataxins
  • Behavior, Animal / physiology
  • Blotting, Western
  • Calbindin 1
  • Calbindins
  • Cell Membrane / metabolism
  • Cell Nucleus / metabolism
  • Cytosol / metabolism
  • DNA Footprinting
  • Female
  • Immunohistochemistry
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Microarray Analysis
  • Mutation / physiology
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism
  • Parvalbumins / metabolism
  • Phenotype
  • Polymerase Chain Reaction
  • Postural Balance / physiology
  • Psychomotor Performance / physiology
  • S100 Calcium Binding Protein G / biosynthesis*
  • S100 Calcium Binding Protein G / genetics
  • Spinocerebellar Ataxias / genetics*
  • Spinocerebellar Ataxias / physiopathology*


  • Ataxin-1
  • Ataxins
  • Atxn1 protein, mouse
  • Calb1 protein, mouse
  • Calbindin 1
  • Calbindins
  • Nerve Tissue Proteins
  • Nuclear Proteins
  • Parvalbumins
  • S100 Calcium Binding Protein G