A small unstructured nucleic acid disrupts a trinucleotide repeat hairpin

作者：Avila Figueroa Amalia; Cattie Douglas; Delaney Sarah^*

来源：Biochemical and Biophysical Research Communications, 2011, 413(4): 532-536.

DOI：10.1016/j.bbrc.2011.08.130

• Trinucleotide repeat expansion
• Strand invasion
• Molecular beacon
• Polyglutamine disorders

A variety of neurodegenerative disorders are associated with the expansion of trinucleotide repeat (TNR) sequences. These repetitive sequences are prone to adopting non-canonical structures, such as intra-strand stem-loop hairpins. Indeed, the formation and persistence of these hairpins during DNA replication and/or repair have been proposed as factors that facilitate TNR expansion. Given this proposed contribution of TNR hairpins to the expansion mechanism, disruption of such structures via strand invasion offers a potential means to negate the disease-initiating expansion. In this work, we investigated the strand invading abilities of a (CTG)(3) unstructured nucleic acid on a (CAG)(10) TNR hairpin. Using fluorescence, optical, and electrophoretic methods, instantaneous disruption of the (CAG)(10) hairpin by (CTG)(3) was observed at low temperatures. Additionally, we have identified three distinct duplex-like species that form between (CAG)(10), and (CTG)(3); these include 1, 2, or 3 (CTG)(3) sequences hybridized to (CAG)(10). The results presented here showcase (CTG)(3) as an invader of a TNR hairpin and suggest that unstructured nucleic acids could serve as a scaffold to design agents to prevent TNR expansion.

• 出版日期2011-10-7