Fission yeast Dna2 is required for generation of the telomeric single-strand overhang

Mol Cell Biol. 2004 Nov;24(21):9557-67. doi: 10.1128/MCB.24.21.9557-9567.2004.

Abstract

It has been suggested that the Schizosaccharomyces pombe Rad50 (Rad50-Rad32-Nbs1) complex is required for the resection of the C-rich strand at telomere ends in taz1-d cells. However, the nuclease-deficient Rad32-D25A mutant can still resect the C-rich strand, suggesting the existence of a nuclease that resects the C-rich strand. Here, we demonstrate that a taz1-d dna2-2C double mutant lost the G-rich overhang at a semipermissive temperature. The amount of G-rich overhang in S phase in the dna2-C2 mutant was lower than that in wild-type cells at the semipermissive temperature. Dna2 bound to telomere DNA in a chromatin immunoprecipitation assay. Moreover, telomere length decreased with each generation after shift of the dna2-2C mutant to the semipermissive temperature. These results suggest that Dna2 is involved in the generation of G-rich overhangs in both wild-type cells and taz1-d cells. The dna2-C2 mutant was not gamma ray sensitive at the semipermissive temperature, suggesting that the ability to process double-strand break (DSB) ends was not affected in the dna2-C2 mutant. Our results reveal that DSB ends and telomere ends are processed by different mechanisms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Bleomycin / pharmacology
  • DNA Repair
  • DNA, Single-Stranded / genetics
  • DNA, Single-Stranded / metabolism*
  • DNA-Binding Proteins
  • Flap Endonucleases / genetics
  • Flap Endonucleases / metabolism*
  • Guanosine / metabolism
  • Mutation / genetics
  • Protein Binding
  • Schizosaccharomyces / cytology
  • Schizosaccharomyces / drug effects
  • Schizosaccharomyces / genetics
  • Schizosaccharomyces / metabolism*
  • Schizosaccharomyces / radiation effects
  • Schizosaccharomyces pombe Proteins / genetics
  • Schizosaccharomyces pombe Proteins / metabolism*
  • Telomerase / metabolism
  • Telomere / genetics*
  • Telomere / metabolism
  • Temperature

Substances

  • DNA, Single-Stranded
  • DNA-Binding Proteins
  • Schizosaccharomyces pombe Proteins
  • trt1 protein, S pombe
  • Bleomycin
  • Guanosine
  • Telomerase
  • Dna2 protein, S pombe
  • Flap Endonucleases