Ataxin 1 and ataxin 3 in neuronal intranuclear inclusion disease

Neuronal intranuclear inclusion disease (NIID) Is a multisystem neurodegene rative disorder characterized by large intranuclear aggregates in neurons o f the central and peripheral nervous system. These ubiquitinated intranucle ar inclusions are morphologically similar to the intraneuronal aggregates t hat have been identified in the CAG/polyglutamine expansion diseases. As ra re aggregates in NIID contain a polyglutamine epitope, we further investiga ted the relationship between this disease and the CAG/polyglutamine expansi on diseases. Here, we show that ataxin 1 and ataxin 3 proteins are recruite d into aggregates in NIID in the absence of a CAG expansion in the SCA1 and SCA3 genes. These data support an association of NIID with the polyglutami ne disorders and provide evidence of in vivo recruitment of proteins with p olyglutamine tracts into intraneuronal aggregates.