TNR (Trinucleotide Repeat) antibodies are specialized tools developed to study neurodegenerative and neuromuscular disorders linked to abnormal expansions of repetitive DNA sequences. These disorders, including Huntington’s disease, fragile X syndrome, and spinocerebellar ataxias, involve unstable trinucleotide repeats (e.g., CAG, CGG) within specific genes, leading to toxic protein aggregates or functional deficits. TNR antibodies target epitopes within these expanded repeats or associated proteins, enabling detection of pathological features like intranuclear inclusions or cytoplasmic aggregates in cellular and animal models.
Their development stemmed from the need to visualize and quantify repeat-containing proteins in research and diagnostics. For example, anti-polyglutamine (polyQ) antibodies, a subset of TNR antibodies, bind expanded CAG repeat-encoded polyQ tracts in mutant huntingtin or ataxin-1. aiding in mechanistic studies of neuronal toxicity. Similarly, antibodies against FMR1 gene products help characterize fragile X-associated pathologies.
TNR antibodies are pivotal in elucidating disease mechanisms, such as protein misfolding, RNA toxicity, and cellular stress responses. They are used in techniques like immunohistochemistry, Western blotting, and flow cytometry to assess disease progression or therapeutic efficacy in preclinical models. Recent advancements include conformation-specific antibodies that distinguish pathological protein isoforms, offering insights into selective targeting strategies. Despite challenges like cross-reactivity, TNR antibodies remain indispensable for advancing research and developing biomarkers for repeat expansion disorders.