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Relative contribution of four nucleases, CtIP, Dna2, Exo1 and Mre11, to the initial step of DNA double‐strand break repair by homologous recombination in both the chicken DT40 and human TK6 cell lines
Author(s) -
Hoa Nguyen Ngoc,
Akagawa Remi,
Yamasaki Tomomi,
Hirota Kouji,
Sasa Kentaro,
Natsume Toyoaki,
Kobayashi Junya,
Sakuma Tetsushi,
Yamamoto Takashi,
Komatsu Kenshi,
Kanemaki Masato T.,
Pommier Yves,
Takeda Shunichi,
Sasanuma Hiroyuki
Publication year - 2015
Publication title -
genes to cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.912
H-Index - 115
eISSN - 1365-2443
pISSN - 1356-9597
DOI - 10.1111/gtc.12310
Subject(s) - homologous recombination , biology , dna repair , dna , rad50 , recombinant dna , saccharomyces cerevisiae , gene , microbiology and biotechnology , non homologous end joining , genetics , dna binding protein , transcription factor
Homologous recombination (HR) is initiated by double‐strand break (DSB) resection, during which DSBs are processed by nucleases to generate 3′ single‐strand DNA. DSB resection is initiated by CtIP and Mre11 followed by long‐range resection by Dna2 and Exo1 in Saccharomyces cerevisiae . To analyze the relative contribution of four nucleases, CtIP, Mre11, Dna2 and Exo1, to DSB resection, we disrupted genes encoding these nucleases in chicken DT40 cells. CtIP and Dna2 are required for DSB resection, whereas Exo1 is dispensable even in the absence of Dna2, which observation agrees with no developmental defect in Exo1‐deficient mice. Despite the critical role of Mre11 in DSB resection in S. cerevisiae , loss of Mre11 only modestly impairs DSB resection in DT40 cells. To further test the role of CtIP and Mre11 in other species, we conditionally disrupted CtIP and MRE11 genes in the human TK6 B cell line. As with DT40 cells, CtIP contributes to DSB resection considerably more significantly than Mre11 in TK6 cells. Considering the critical role of Mre11 in HR, this study suggests that Mre11 is involved in a mechanism other than DSB resection. In summary, CtIP and Dna2 are sufficient for DSB resection to ensure efficient DSB repair by HR.