Break-induced replication and recombinational telomere elongation in yeast

Annu Rev Biochem. 2006;75:111-35. doi: 10.1146/annurev.biochem.74.082803.133234.


When a telomere becomes unprotected or if only one end of a chromosomal double-strand break succeeds in recombining with a template sequence, DNA can be repaired by a recombination-dependent DNA replication process termed break-induced replication (BIR). In budding yeasts, there are two BIR pathways, one dependent on the Rad51 recombinase protein and one Rad51 independent; these two repair processes lead to different types of survivors in cells lacking the telomerase enzyme that is required for normal telomere maintenance. Recombination at telomeres is triggered by either excessive telomere shortening or disruptions in the function of telomere-binding proteins. Telomere elongation by BIR appears to often occur through a "roll and spread" mechanism. In this process, a telomeric circle produced by recombination at a dysfunctional telomere acts as a template for a rolling circle BIR event to form an elongated telomere. Additional BIR events can then copy the elongated sequence to all other telomeres.

Publication types

  • Research Support, N.I.H., Extramural
  • Review

MeSH terms

  • Cell Cycle / physiology
  • Cellular Senescence
  • DNA Damage*
  • DNA Replication*
  • DNA, Mitochondrial / genetics
  • Genes, cdc
  • Humans
  • Rad51 Recombinase / metabolism
  • Recombination, Genetic*
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism
  • Telomere / metabolism*


  • DNA, Mitochondrial
  • Saccharomyces cerevisiae Proteins
  • Rad51 Recombinase