Abstract
Spinocerebellar ataxia type 1 (SCA1) is a dominant neurodegenerative disease caused by the expression of mutant ataxin-1 containing an expanded polyglutamine tract. Ataxin-1 is a nuclear protein that localizes to punctate inclusions similar to neuronal nuclear inclusions seen in many polyglutamine expansion disease proteins. We demonstrate that ataxin-1 localization to inclusions and inclusion dynamics within the nucleus are RNA and transcription dependent, but not dependent on the polyglutamine tract. Ataxin-1 nuclear inclusions are distinct from other described nuclear bodies but recruit the mRNA export factor, TAP/NXF1, in a manner that is enhanced by cell heat shock. By FRAP protein dynamic studies in live cells, we found that wild-type, but not mutant, ataxin-1 was capable of nuclear export. These results suggest that the normal role of ataxin-1 may be in RNA processing, perhaps nuclear RNA export. Thus, nuclear retention of mutant ataxin-1 may be an important toxic gain of function in SCA1 disease.
Original language | English (US) |
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Pages (from-to) | 233-242 |
Number of pages | 10 |
Journal | Journal of cell science |
Volume | 118 |
Issue number | 1 |
DOIs | |
State | Published - Jan 1 2005 |
Keywords
- Ataxin-1
- Nuclear transport
- RNA processing
- Spinocerebellar ataxia type 1