Abstract
Objective: Huntington's disease-like 2 (HDL2) is caused by a CAG/CTG expansion mutation on chromosome 16q24.3. The repeat falls, in the CTG orientation, within a variably spliced exon of junctophilin-3 (JPH3). The existence of a JPH3 splice variant with the CTG repeat in 3′ untranslated region suggested that transcripts containing an expanded CUG repeat could play a role in the pathogenesis of HDL2, similar to the proposed pathogenic role of expanded CUG repeats in myotonic dystrophy type 1 (DM1). The goal of this study, therefore, was to test the plausibility of an RNA gain-of-function component in the pathogenesis of HDL2. Methods: The presence and composition of RNA foci in frontal cortex from HDL2, Huntington's disease, DMI, and control brains were investigated by in situ hybridization and immunohistochemistry. An untranslatable JPH3 transcript containing either a normal or an expanded CUG repeat was engineered and expressed in human embryonic kidney 293 and HT22 cells to further test the toxic RNA hypothesis. The formation of RNA foci and the extent of cell death were quantified. Results: RNA foci resembling DM1 foci were detected in neurons in HDL2 cortex and other brain regions. Similar to DMI, the foci colocalize with muscleblind-like protein 1, and nuclear muscleblind-like protein 1 in HDL2 cortical neurons is decreased relative to controls. In cell experiments, expression of a JPH3 transcript with an expanded CUG repeat resulted in the formation of RNA foci that colocalized with muscleblind-like protein 1 and in cell toxicity. Interpretation: These results imply that RNA toxicity may contribute to the pathogenesis of HDL2.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 272-282 |
| Number of pages | 11 |
| Journal | Annals of Neurology |
| Volume | 61 |
| Issue number | 3 |
| DOIs | |
| State | Published - Mar 2007 |
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ASJC Scopus subject areas
- Neuroscience(all)
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Huntington's disease-like 2 is associated with CUG repeat-containing RNA foci. / Rudnicki, Dobrila D.; Holmes, Susan E.; Lin, Mark W.; Thornton, Charles A.; Ross, Christopher A; Margolis, Russell Louis.
In: Annals of Neurology, Vol. 61, No. 3, 03.2007, p. 272-282.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Huntington's disease-like 2 is associated with CUG repeat-containing RNA foci
AU - Rudnicki, Dobrila D.
AU - Holmes, Susan E.
AU - Lin, Mark W.
AU - Thornton, Charles A.
AU - Ross, Christopher A
AU - Margolis, Russell Louis
PY - 2007/3
Y1 - 2007/3
N2 - Objective: Huntington's disease-like 2 (HDL2) is caused by a CAG/CTG expansion mutation on chromosome 16q24.3. The repeat falls, in the CTG orientation, within a variably spliced exon of junctophilin-3 (JPH3). The existence of a JPH3 splice variant with the CTG repeat in 3′ untranslated region suggested that transcripts containing an expanded CUG repeat could play a role in the pathogenesis of HDL2, similar to the proposed pathogenic role of expanded CUG repeats in myotonic dystrophy type 1 (DM1). The goal of this study, therefore, was to test the plausibility of an RNA gain-of-function component in the pathogenesis of HDL2. Methods: The presence and composition of RNA foci in frontal cortex from HDL2, Huntington's disease, DMI, and control brains were investigated by in situ hybridization and immunohistochemistry. An untranslatable JPH3 transcript containing either a normal or an expanded CUG repeat was engineered and expressed in human embryonic kidney 293 and HT22 cells to further test the toxic RNA hypothesis. The formation of RNA foci and the extent of cell death were quantified. Results: RNA foci resembling DM1 foci were detected in neurons in HDL2 cortex and other brain regions. Similar to DMI, the foci colocalize with muscleblind-like protein 1, and nuclear muscleblind-like protein 1 in HDL2 cortical neurons is decreased relative to controls. In cell experiments, expression of a JPH3 transcript with an expanded CUG repeat resulted in the formation of RNA foci that colocalized with muscleblind-like protein 1 and in cell toxicity. Interpretation: These results imply that RNA toxicity may contribute to the pathogenesis of HDL2.
AB - Objective: Huntington's disease-like 2 (HDL2) is caused by a CAG/CTG expansion mutation on chromosome 16q24.3. The repeat falls, in the CTG orientation, within a variably spliced exon of junctophilin-3 (JPH3). The existence of a JPH3 splice variant with the CTG repeat in 3′ untranslated region suggested that transcripts containing an expanded CUG repeat could play a role in the pathogenesis of HDL2, similar to the proposed pathogenic role of expanded CUG repeats in myotonic dystrophy type 1 (DM1). The goal of this study, therefore, was to test the plausibility of an RNA gain-of-function component in the pathogenesis of HDL2. Methods: The presence and composition of RNA foci in frontal cortex from HDL2, Huntington's disease, DMI, and control brains were investigated by in situ hybridization and immunohistochemistry. An untranslatable JPH3 transcript containing either a normal or an expanded CUG repeat was engineered and expressed in human embryonic kidney 293 and HT22 cells to further test the toxic RNA hypothesis. The formation of RNA foci and the extent of cell death were quantified. Results: RNA foci resembling DM1 foci were detected in neurons in HDL2 cortex and other brain regions. Similar to DMI, the foci colocalize with muscleblind-like protein 1, and nuclear muscleblind-like protein 1 in HDL2 cortical neurons is decreased relative to controls. In cell experiments, expression of a JPH3 transcript with an expanded CUG repeat resulted in the formation of RNA foci that colocalized with muscleblind-like protein 1 and in cell toxicity. Interpretation: These results imply that RNA toxicity may contribute to the pathogenesis of HDL2.
UR - http://www.scopus.com/inward/record.url?scp=34147185192&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=34147185192&partnerID=8YFLogxK
U2 - 10.1002/ana.21081
DO - 10.1002/ana.21081
M3 - Article
VL - 61
SP - 272
EP - 282
JO - Annals of Neurology
JF - Annals of Neurology
SN - 0364-5134
IS - 3
ER -