A novel central nervous system-enriched spinocerebellar ataxia type 7 gene product.

CONTEXT: Polyglutamine-mediated neurodegeneration in spinocerebellar ataxia type 7 (SCA7) involves specific central nervous system structures despite widespread expression of the mutant ataxin-7 protein.

OBJECTIVE

To determine whether expression of multiple gene products could contribute to selective neurodegeneration in SCA7.

RESULTS

We identified a novel SCA7 transcript and protein, both of which are enriched within the central nervous system. An isoform-specific antibody revealed that the novel ataxin-7 variant, in contrast with the previously described protein, localizes to neuronal cytoplasm and not to inclusion bodies present within the tissues of patients with SCA7.

CONCLUSIONS

In addition to expanding our understanding of SCA7 gene expression, identification of a novel ataxin-7 protein enriched in the central nervous system suggests that expression of multiple polyglutamine-containing proteins may play a role in generating the neurodegenerative patterns characteristic of SCA7 and other polyglutamine expansion diseases.