Inactivation of the mouse Atxn3 (ataxin-3) gene increases protein ubiquitination.
Spinocerebellar ataxia type 3 is a neurodegenerative disease caused by expansion of a polyglutamine domain in the protein ataxin-3 (ATXN3). Physiological functions of ATXN3 presumably include ubiquitin protease and transcriptional corepressor activity. To gain insight into the function of ATXN3 and to test the hypothesis that loss of ATXN3 contributes to the pathology in SCA3 we generated Atxn3 knockout (ko) mice by targeted mutagenesis. Loss of Atxn3 did not affect viability or fertility and Atxn3 ko mice displayed no overt abnormalities. On the accelerating Rotarod Atxn3 ko mice performed as well as wildtype (wt) animals, but reduced exploratory behavior in the open field suggested a sense of heightened anxiety. While no gross deficits were apparent upon morphological examination, we found increased levels of ubiquitinated proteins in Atxn3 ko tissues. Thus Atxn3 ko mice provide the first in vivo reference to the deubiquitinating activity of ATXN3.
Schmitt
Ina
I
Department of Neurology, University of Bonn, Neurobiology, Sigmund-Freud-Str. 25, 53105 Bonn, Germany. i.schmitt@uni-bonn.de
Linden
Marion
M
Khazneh
Hassan
H
Evert
Bernd O
BO
Breuer
Peter
P
Klockgether
Thomas
T
Wuellner
Ullrich
U
D000818:Animals; D001007:Anxiety; D000067699:Ataxin-3; D001522:Behavior, Animal; D001921:Brain / Q000378:metabolism; D005260:Female; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008954:Models, Biological; D019636:Neurodegenerative Diseases / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000502:physiology*; D010455:Peptides / Q000378:metabolism; D013737:Testis / Q000378:metabolism; D014018:Tissue Distribution; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*; D025801:Ubiquitin / Q000378:metabolism*
D009687:Nuclear Proteins; D010455:Peptides; D014157:Transcription Factors; D025801:Ubiquitin; C097188:polyglutamine; D000067699:Ataxin-3; C511594:Atxn3 protein, mouse