Dramatic mutation instability in HD mouse striatum: does polyglutamine load contribute to cell-specific vulnerability in Huntington's disease?
An unstable CAG triplet repeat expansion encoding a polyglutamine stretch within the ubiquitously expressed protein huntingtin is responsible for causing Huntington's disease (HD). By quantifying the repeat sizes of individual mutant alleles in tissues derived from an accurate genetic mouse model of HD we show that the mutation becomes very unstable in striatal tissue. The expansion-biased changes increase with age, such that some striatal cells from old HD mice contain mutations that have tripled in size. If this pattern of repeat instability is recapitulated in human striatal tissue, the concomitant increased polyglutamine load may contribute to the patterns of selective neuronal cell death in HD. Our findings also suggest that trinucleotide repeat instability can occur by mechanisms that are not replication-based.
Kennedy
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L
Division of Molecular Genetics, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G11 6NU, UK.
Shelbourne
P F
PF
D000483:Alleles; D000818:Animals; D003342:Corpus Striatum / Q000378:metabolism* / Q000473:pathology; D005260:Female; D000071058:Huntingtin Protein; D006816:Huntington Disease / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009154:Mutation; D009410:Nerve Degeneration; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism; D009474:Neurons / Q000378:metabolism / Q000473:pathology; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D010455:Peptides / Q000235:genetics / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D018911:Trinucleotide Repeats
C506812:Htt protein, mouse; D000071058:Huntingtin Protein; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D010455:Peptides; C097188:polyglutamine