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

Tomita Kazunori

Kibe Tatsuya

Kang Ho-Young

Seo Yeon-Soo

Uritani Masahiro

Ushimaru Takashi

Ueno Masaru

Molecular and cellular biology

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.

Biology [ 460 ]

eng

American Society for Microbiology

Copyright (c) American Society for Microbiology

[ISSN] 0270-7306

[NCID] AA10620925

[DOI] 10.1128/MCB.24.21.9557-9567.2004

[PMID] 15485922

[DOI] http://dx.doi.org/10.1128/MCB.24.21.9557-9567.2004 isVersionOf