scholarly journals Repair of ionizing radiation-induced DNA double-strand breaks by non-homologous end-joining

2009 ◽  
Vol 417 (3) ◽  
pp. 639-650 ◽  
Author(s):  
Brandi L. Mahaney ◽  
Katheryn Meek ◽  
Susan P. Lees-Miller

DNA DSBs (double-strand breaks) are considered the most cytotoxic type of DNA lesion. They can be introduced by external sources such as IR (ionizing radiation), by chemotherapeutic drugs such as topoisomerase poisons and by normal biological processes such as V(D)J recombination. If left unrepaired, DSBs can cause cell death. If misrepaired, DSBs may lead to chromosomal translocations and genomic instability. One of the major pathways for the repair of IR-induced DSBs in mammalian cells is NHEJ (non-homologous end-joining). The main proteins required for NHEJ in mammalian cells are the Ku heterodimer (Ku70/80 heterodimer), DNA-PKcs [the catalytic subunit of DNA-PK (DNA-dependent protein kinase)], Artemis, XRCC4 (X-ray-complementing Chinese hamster gene 4), DNA ligase IV and XLF (XRCC4-like factor; also called Cernunnos). Additional proteins, including DNA polymerases μ and λ, PNK (polynucleotide kinase) and WRN (Werner's Syndrome helicase), may also play a role. In the present review, we will discuss our current understanding of the mechanism of NHEJ in mammalian cells and discuss the roles of DNA-PKcs and DNA-PK-mediated phosphorylation in NHEJ.

2008 ◽  
Vol 36 (8) ◽  
pp. 2561-2569 ◽  
Author(s):  
Leonie Schulte-Uentrop ◽  
Raafat A. El-Awady ◽  
Lena Schliecker ◽  
Henning Willers ◽  
Jochen Dahm-Daphi

DNA Repair ◽  
2006 ◽  
Vol 5 (6) ◽  
pp. 741-749 ◽  
Author(s):  
Kyoko Nakamura ◽  
Wataru Sakai ◽  
Takuo Kawamoto ◽  
Ronan T. Bree ◽  
Noel F. Lowndes ◽  
...  

Author(s):  
Roopa Thapar

DNA double-strand breaks (DSBs) are deleterious lesions that are generated in response to ionizing radiation or replication fork collapse that can lead to genomic instability and cancer.  Eukaryotes have evolved two major pathways, namely homologous recombination (HR) and non-homologous end joining (NHEJ) to repair DSBs.  Whereas the roles of protein-DNA interactions in HR and NHEJ have been fairly well defined, the functions of small and long non-coding RNAs and RNA-DNA hybrids in the DNA damage response is just beginning to be elucidated.  This review summarizes recent discoveries on the identification of non-coding RNAs and RNA-mediated regulation of DSB repair


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