ATXN7 and Machado-Joseph disease: Impairment of the UPS has been observed in vivo in a C.elegans spinocerebellar ataxia 3 (SCA3) model using a GFPu UPS reporter [28], while contrasting evidence from an SCA7 mouse model shows that polyglutamine pathogenesis can occur in the absence of significant UPS impairment, as detected by a UFD reporter [29].