Trinucleotide repeats that expand in human disease form hairpin structures in vitro

Cell. 1995 May 19;81(4):533-40. doi: 10.1016/0092-8674(95)90074-8.


We show that repeating units from all reported disease genes are capable of forming hairpins of common structure and threshold stability. The threshold stability is roughly -50 kcal per hairpin and is influenced by the flanking sequence of the gene. Hairpin stability has two components, sequence and length; only DNA of select sequences and the correct length can form hairpins of threshold energy. There is a correlation among the ability to form hairpins of threshold stability, the sequence selectivity of expansion, and the length dependence of expansion. Additionally, hairpin formation provides a potential structural basis for the constancy of the CCG region of the Huntington's disease gene in individuals and explains the stabilizing effects of AGG interruptions in FMR1 alleles.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Base Sequence
  • Genetic Diseases, Inborn / genetics*
  • Humans
  • Molecular Sequence Data
  • Repetitive Sequences, Nucleic Acid*
  • Sequence Analysis