Cdc13 prevents telomere uncapping and Rad50-dependent homologous recombination

EMBO J. 2001 Nov 1;20(21):6127-39. doi: 10.1093/emboj/20.21.6127.

Abstract

Cdc13 performs an essential function in telomere end protection in budding yeast. Here, we analyze the consequences on telomere dynamics of cdc13-induced telomeric DNA damage in proliferating cells. Checkpoint-deficient cdc13-1 cells accumulated DNA damage and eventually senesced. However, these telomerase-proficient cells could survive by using homologous recombination but, contrary to telomerase-deficient cells, did so without prior telomere shortening. Strikingly, homologous recombination in cdc13-1 mec3, as well as in telomerase-deficient cdc13-1 cells, which were Rad52- and Rad50-dependent but Rad51-independent, exclusively amplified the TG(1-3) repeats. This argues that not only short telomeres are substrates for type II recombination. The Cdc13-1 mutant protein harbored a defect in its association with Stn1 and Ten1 but also an additional, unknown, defect that could not be cured by expressing a Cdc13-1- Ten1-Stn1 fusion. We propose that Cdc13 prevents telomere uncapping and inhibits recombination between telomeric sequences through a pathway distinct from and complementary to that used by telomerase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Cycle Proteins / metabolism
  • Cell Survival / physiology
  • Cellular Senescence / physiology
  • Cyclin B / genetics
  • Cyclin B / metabolism*
  • DNA Damage / physiology
  • DNA-Binding Proteins / metabolism
  • Fungal Proteins / metabolism*
  • Genes, cdc
  • Mutation
  • Rad51 Recombinase
  • Rad52 DNA Repair and Recombination Protein
  • Recombination, Genetic / physiology*
  • Saccharomyces cerevisiae
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism
  • Telomerase / metabolism
  • Telomere / genetics
  • Telomere / metabolism*
  • Telomere-Binding Proteins*
  • Temperature

Substances

  • Cell Cycle Proteins
  • Cyclin B
  • DNA-Binding Proteins
  • Fungal Proteins
  • MEC3 protein, S cerevisiae
  • RAD50 protein, S cerevisiae
  • RAD52 protein, S cerevisiae
  • Rad52 DNA Repair and Recombination Protein
  • Saccharomyces cerevisiae Proteins
  • Stn1 protein, S cerevisiae
  • Telomere-Binding Proteins
  • RAD51 protein, S cerevisiae
  • Rad51 Recombinase
  • Telomerase