CAG-polyglutamine-repeat mutations: independence from gene context

Several neurological disorders have been attributed to the inheritance of l ong CAG-polyglutamine repeats. Unlike classical mutations, whose deleteriou s effects are totally dependent on the context of the gene in which they re side, these translated CAG repeat mutations have been shown to cause neurot oxicity and neuronal intranuclear inclusions when expressed outside their n atural gene context. We provide a description of mice with different length s of repeat in the foreign context of the murine Hprt locus, focusing on as pects of the phenotype that provide an insight into the mechanism by which this unusual mutation might cause toxicity.