Two sequential cleavage reactions on cruciform DNA structures cause palindrome-mediated chromosomal translocations

Nat Commun. 2013;4:1592. doi: 10.1038/ncomms2595.

Abstract

Gross chromosomal rearrangements (GCRs), such as translocations, deletions or inversions, are often generated by illegitimate repair between two DNA breakages at regions with nucleotide sequences that might potentially adopt a non-B DNA conformation. We previously established a plasmid-based model system that recapitulates palindrome-mediated recurrent chromosomal translocations in humans, and demonstrated that cruciform DNA conformation is required for the translocation-like rearrangements. Here we show that two sequential reactions that cleave the cruciform structures give rise to the translocation: GEN1-mediated resolution that cleaves diagonally at the four-way junction of the cruciform and Artemis-mediated opening of the subsequently formed hairpin ends. Indeed, translocation products in human sperm reveal the remnants of this two-step mechanism. These two intrinsic pathways that normally fulfil vital functions independently, Holliday-junction resolution in homologous recombination and coding joint formation in rearrangement of antigen-receptor genes, act upon the unusual DNA conformation in concert and lead to a subset of recurrent GCRs in humans.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • AT Rich Sequence
  • Base Sequence
  • Blotting, Southern
  • Chromosome Breakage
  • DNA, Cruciform / chemistry
  • DNA, Cruciform / genetics
  • DNA, Cruciform / metabolism*
  • DNA-Binding Proteins
  • Endonucleases
  • Gene Knockdown Techniques
  • Gene Rearrangement / genetics
  • HEK293 Cells
  • Holliday Junction Resolvases / metabolism
  • Humans
  • Inverted Repeat Sequences / genetics*
  • Male
  • Models, Biological
  • Molecular Sequence Data
  • Nuclear Proteins / metabolism
  • Nucleotides / genetics
  • Spermatozoa / metabolism
  • Translocation, Genetic / genetics*

Substances

  • DNA, Cruciform
  • DNA-Binding Proteins
  • Nuclear Proteins
  • Nucleotides
  • DCLRE1C protein, human
  • Endonucleases
  • GEN1 protein, human
  • Holliday Junction Resolvases