SCA1-like disease in mice expressing wild-type ataxin-1 with a serine to aspartic acid replacement at residue 776.
Glutamine tract expansion triggers nine neurodegenerative diseases by conferring toxic properties to the mutant protein. In SCA1, phosphorylation of ATXN1 at Ser776 is thought to be key for pathogenesis. Here, we show that replacing Ser776 with a phosphomimicking Asp converted ATXN1 with a wild-type glutamine tract into a pathogenic protein. ATXN1[30Q]-D776-induced disease in Purkinje cells shared most features with disease caused by ATXN1[82Q] having an expanded polyglutamine tract. However, in contrast to disease induced by ATXN1[82Q] that progresses to cell death, ATXN1[30Q]-D776 failed to induce cell death. These results support a model where pathogenesis involves changes in regions of the protein in addition to the polyglutamine tract. Moreover, disease initiation and progression to neuronal dysfunction are distinct from induction of cell death. Ser776 is critical for the pathway to neuronal dysfunction, while an expanded polyglutamine tract is essential for neuronal death.
Duvick
Lisa
L
Institute of Translational Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA; Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455, USA.
Barnes
Justin
J
Ebner
Blake
B
Agrawal
Smita
S
Andresen
Michael
M
Lim
Janghoo
J
Giesler
Glenn J
GJ
Zoghbi
Huda Y
HY
Orr
Harry T
HT
D000818:Animals; D001224:Aspartic Acid / Q000235:genetics*; D000067696:Ataxin-1; D000067528:Ataxins; D064026:Calbindins; D002531:Cerebellum / Q000473:pathology; D003712:Dendrites / Q000378:metabolism; D004195:Disease Models, Animal; D005786:Gene Expression Regulation / Q000235:genetics; D051379:Mice; D008822:Mice, Transgenic; D009043:Motor Activity / Q000235:genetics; D009154:Mutation / Q000235:genetics*; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism*; D009434:Neural Pathways / Q000378:metabolism / Q000473:pathology; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism*; D011689:Purkinje Cells / Q000473:pathology / Q000648:ultrastructure; D045442:Rotarod Performance Test; D064030:S100 Calcium Binding Protein G / Q000378:metabolism; D012694:Serine / Q000235:genetics*; D020754:Spinocerebellar Ataxias / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology; D050599:Vesicular Glutamate Transport Protein 2 / Q000378:metabolism
D000067696:Ataxin-1; D000067528:Ataxins; C000593750:Atxn1 protein, mouse; D064026:Calbindins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D064030:S100 Calcium Binding Protein G; C493477:Slc17a6 protein, mouse; D050599:Vesicular Glutamate Transport Protein 2; D001224:Aspartic Acid; D012694:Serine