Trinucleotide repeat (TNR) expansion is the causative mutation for at least 17 inherited neurological diseases. An important question in the field is which proteins drive the expansion process. This study reports that the multi-functional protein Sem1 is a novel driver of TNR expansions in budding yeast. Mutants of SEM1 suppress up to 90% of expansions. Subsequent analysis showed that Sem1 faci...

Spinocerebellar Ataxia type 3 (SCA3) or Machado-Joseph disease (MJD) is one of the most common polyglutamine (polyQ) diseases, which comprise a group of inherited neurodegenerative conditions characterized by the pathological expansion of CAG trinucleotide repeats in the translated regions of unrelated genes. The expansion of a (CAG) tract in the coding region of the causative gene MJD1, transl...

| The underlying genetic mutations for many inherited neurodegenerative disorders have been identified in recent years. One frequent type of mutation is trinucleotide repeat expansion. Depending on the location of the repeat expansion, the mutation might result in a loss of function of the disease gene, a toxic gain of function or both. Disease gene identification has led to the development of ...

Huntington's disease (HD) is a neurodegenerative disorder characterized by a triad of choreoathetosis, dementia and dominant inheritance. The cause of HD is an expansion of CAG trinucleotide repeats in the HD gene. Typical age at onset of symptoms is in the 40s, but the disorder can manifest at any time. Late-onset (≥ 60 years) HD is clinically different from other adult or juvenile onset HD an...

Spinocerebellar ataxia type 8 (SCA8) is a neurodegenerative disorder characterized by slowly progressive cerebellar ataxia. It is caused by bidirectional expression of (CUG)n expansion in the ATXN80S/ATXN8 gene and (CAG)n expansion transcripts in ATXN8. The diagnosis of SCA8 must be confirmed by the presence of a (CTG)n trinucleotide repeat expansion in the ATXN8OS gene. On the other hand, ther...

Trinucleotide, or triplet, repeats consist of 3 nucleotides consecutively repeated (e.g., CAG CAG CAG CAG) within a region of DNA. All possible combinations of nucleotides are known to exist as triplet repeats, although some are more common than others. These repeated sequences are found both within gene boundaries and in the large stretches of DNA that lie benveen genes. If the triplet repeats...

Expansion of trinucleotide repeats has been identified as a common mechanism of hereditary neurodegenerative diseases including spinal and bulbar muscular atrophy (SBMA), Huntington's disease, dentatorubral-pallidoluysian atrophy (DRPLA), Machado-Joseph disease (MJD), fragile X syndrome, myotonic dystrophy and Friedreich's ataxia. These diseases share unique features, which are difficult to exp...

Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by a CAG trinucleotide repeat expansion in the huntingtin gene. Major pathological hallmarks of HD include inclusions of mutant huntingtin (mHTT) protein, loss of neurons predominantly in the caudate nucleus, and atrophy of multiple brain regions. However, the early sequence of histological events that manifest...