UTteR control through miRs: fine-tuning ATXN1 levels to prevent ataxia.

Pathomechanistic studies of neurodegenerative diseases have documented the toxic effects of mutant protein expression, misfolding, and aggregation. However, alterations in the expression of the corresponding wild-type (WT) gene, due to either variations in copy number or transcriptional regulation, have also been linked to Alzheimer's and Parkinson's diseases. Another striking example of this mutant and WT duality is spinocerebellar ataxia type 1 (SCA1) caused by an ATXN1 polyglutamine protein, although subtle variations in WT AXTN1 levels also lead to ataxia. In this issue of Genes & Development, Nitschke and colleagues (pp. 1147-1160) delve into posttranscriptional events that fine-tune ATXN1 expression and uncover a key role for 5' untranslated region (5' UTR)-miR760 interactions. Thus, this study not only provides significant insights into the complexities of modulating the expression of a dosage-sensitive gene but also highlights the critical importance of identifying noncoding polymorphisms as disease risk factors.