TY - JOUR
T1 - Persistently bound Ku at DNA ends attenuates DNA end resection and homologous recombination
AU - Shao, Zhengping
AU - Davis, Anthony J.
AU - Fattah, Kazi R.
AU - So, Sairei
AU - Sun, Jingxin
AU - Lee, Kyung Jong
AU - Harrison, Lynn
AU - Yang, Jun
AU - Chen, David J.
N1 - Funding Information:
The authors are grateful to Austin DeBeaux and Reneau Castore from the Harrison laboratory for the creation of the Mt-Ku-EGFP and NLS fusion and FLAG-Mt-Ku-NLS open reading frame expression vectors. The research was supported by National Institutes of Health grants ( CA50519, CA134991, and CA92584 ) and Cancer Prevention Research Institute of Texas ( RP110465 ) to DJC and National Institutes of Health grants are CA85693 and CA85693-9S1 to LH. ZS was supported by a fellowship from the China Scholarship Council.
PY - 2012/3/1
Y1 - 2012/3/1
N2 - DNA double strand breaks (DSBs) are repaired by non-homologous end joining (NHEJ) or homologous recombination (HR). The DNA cell cycle stage and resection of the DSB ends are two key mechanisms which are believed to push DSB repair to the HR pathway. Here, we show that the NHEJ factor Ku80 associates with DSBs in S phase, when HR is thought to be the preferred repair pathway, and its dynamics/kinetics at DSBs is similar to those observed for Ku80 in non-S phase in mammalian cells. A Ku homolog from Mycobacterium tuberculosis binds to and is retained at DSBs in S phase and was used as a tool to determine if blocking DNA ends affects end resection and HR in mammalian cells. A decrease in DNA end resection, as marked by IR-induced RPA, BrdU, and Rad51 focus formation, and HR are observed when Ku deficient rodent cells are complemented with Mt-Ku. Together, this data suggests that Ku70/80 binds to DSBs in all cell cycle stages and is likely actively displaced from DSB ends to free the DNA ends for DNA end resection and thus HR to occur.
AB - DNA double strand breaks (DSBs) are repaired by non-homologous end joining (NHEJ) or homologous recombination (HR). The DNA cell cycle stage and resection of the DSB ends are two key mechanisms which are believed to push DSB repair to the HR pathway. Here, we show that the NHEJ factor Ku80 associates with DSBs in S phase, when HR is thought to be the preferred repair pathway, and its dynamics/kinetics at DSBs is similar to those observed for Ku80 in non-S phase in mammalian cells. A Ku homolog from Mycobacterium tuberculosis binds to and is retained at DSBs in S phase and was used as a tool to determine if blocking DNA ends affects end resection and HR in mammalian cells. A decrease in DNA end resection, as marked by IR-induced RPA, BrdU, and Rad51 focus formation, and HR are observed when Ku deficient rodent cells are complemented with Mt-Ku. Together, this data suggests that Ku70/80 binds to DSBs in all cell cycle stages and is likely actively displaced from DSB ends to free the DNA ends for DNA end resection and thus HR to occur.
KW - DNA double-strand breaks
KW - DNA end resection
KW - Homologous recombination
KW - Ku70/80
KW - Non-homologous end-joining
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U2 - 10.1016/j.dnarep.2011.12.007
DO - 10.1016/j.dnarep.2011.12.007
M3 - Article
C2 - 22265216
AN - SCOPUS:84862777942
SN - 1568-7864
VL - 11
SP - 310
EP - 316
JO - DNA repair
JF - DNA repair
IS - 3
ER -