Patching broken chromosomes with extranuclear cellular DNA

Mol Cell. 1999 Nov;4(5):873-81. doi: 10.1016/s1097-2765(00)80397-4.

Abstract

Chromosomal double-strand breaks (DSBs) can be repaired by either homology-dependent or homology-independent pathways. Using a novel intron-based genetic assay to identify rare homology-independent DNA rearrangements associated with repair of a chromosomal DSB in S. cerevisiae, we observed that approximately 20% of rearrangements involved endogenous DNA insertions at the break site. We have analyzed 37 inserts and find they fall into two distinct classes: Ty1 cDNA intermediates varying in length from 140 bp to 3.4 kb and short mitochondrial DNA fragments ranging in size from 33 bp to 219 bp. Several inserts consist of multiple noncontiguous mitochondrial DNA segments. These results demonstrate an ongoing mechanism for genome evolution through acquisition of organellar and mobile DNAs at DSB sites.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Cell Nucleus / drug effects
  • Cell Nucleus / enzymology
  • Cell Nucleus / genetics
  • Chromosome Breakage / genetics*
  • Chromosomes, Fungal / drug effects
  • Chromosomes, Fungal / genetics
  • DNA Repair / drug effects
  • DNA Repair / genetics*
  • DNA, Fungal / genetics*
  • DNA, Mitochondrial / genetics*
  • Deoxyribonucleases, Type II Site-Specific / metabolism
  • Enzyme Induction / drug effects
  • Evolution, Molecular
  • Galactose / pharmacology
  • Genes, Fungal / genetics
  • Introns / genetics
  • Molecular Weight
  • Mutation / genetics
  • Recombination, Genetic / drug effects
  • Recombination, Genetic / genetics
  • Retroelements / genetics*
  • Saccharomyces cerevisiae / cytology
  • Saccharomyces cerevisiae / drug effects
  • Saccharomyces cerevisiae / enzymology
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae Proteins
  • Sequence Homology, Nucleic Acid

Substances

  • DNA, Fungal
  • DNA, Mitochondrial
  • Retroelements
  • Saccharomyces cerevisiae Proteins
  • SCEI protein, S cerevisiae
  • Deoxyribonucleases, Type II Site-Specific
  • Galactose