Fission yeast Dna2 is required for generation of the telomeric single-strand overhang.
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.
Tomita
Kazunori
K
Department of Chemistry, Faculty of Science, Shizuoka University, 836 Oya, Shizuoka 422-8529, Japan.
Kibe
Tatsuya
T
Kang
Ho-Young
HY
Seo
Yeon-Soo
YS
Uritani
Masahiro
M
Ushimaru
Takashi
T
Ueno
Masaru
M
D001483:Base Sequence; D001761:Bleomycin / Q000494:pharmacology; D004260:DNA Repair; D004277:DNA, Single-Stranded / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins; D045585:Flap Endonucleases / Q000235:genetics / Q000378:metabolism*; D006151:Guanosine / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D011485:Protein Binding; D012568:Schizosaccharomyces / Q000166:cytology / Q000187:drug effects / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism*; D019098:Telomerase / Q000378:metabolism; D016615:Telomere / Q000235:genetics* / Q000378:metabolism; D013696:Temperature
D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D029702:Schizosaccharomyces pombe Proteins; C509188:trt1 protein, S pombe; D001761:Bleomycin; D006151:Guanosine; D019098:Telomerase; C493531:Dna2 protein, S pombe; D045585:Flap Endonucleases