Ku regulates the non-homologous end joining pathway choice of DNA double-strand break repair in human somatic cells

Farjana Fattaha, Eu Han Lee, Natalie Weisenselb, Yongbao Wang, Natalie Lichter, Eric A Hendrickson

Research output: Contribution to journalArticle

158 Citations (Scopus)

Abstract

The repair of DNA double-strand breaks (DSBs) is critical for the maintenance of genomic integrity and viability for all organisms. Mammals have evolved at least two genetically discrete ways to mediate DNA DSB repair: homologous recombination (HR) and non-homologous end joining (NHEJ). In mammalian cells, most DSBs are preferentially repaired by NHEJ. Recent work has demonstrated that NHEJ consists of at least two sub-pathways - the main Ku heterodimerdependent or "classic" NHEJ (C-NHEJ) pathway and an "alternative" NHEJ (A-NHEJ) pathway, which usually generates microhomology-mediated signatures at repair junctions. In our study, recombinant adeno-associated virus knockout vectors were utilized to construct a series of isogenic human somatic cell lines deficient in the core C-NHEJ factors (Ku, DNA-PKcs, XLF, and LIGIV), and the resulting cell lines were characterized for their ability to carry out DNA DSB repair. The absence of DNA-PKcs, XLF, or LIGIV resulted in cell lines that were profoundly impaired in DNA DSB repair activity. Unexpectedly, Ku86-null cells showed wild-type levels of DNA DSB repair activity that was dominated by microhomology joining events indicative of A-NHEJ. Importantly, A-NHEJ DNA DSB repair activity could also be efficiently de-repressed in LIGIV-null and DNA-PKcs-null cells by subsequently reducing the level of Ku70. These studies demonstrate that in human cells C-NHEJ is the major DNA DSB repair pathway and they show that Ku is the critical C-NHEJ factor that regulates DNA NHEJ DSB pathway choice.

Original languageEnglish (US)
Article numbere1000855
JournalPLoS genetics
Volume6
Issue number2
DOIs
StatePublished - Feb 1 2010

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Double-Stranded DNA Breaks
somatic cells
repair
DNA
Null Lymphocytes
Cell Line
DNA End-Joining Repair
cell lines
Dependovirus
Recombinational DNA Repair
cells
Mammals
homologous recombination
Maintenance
DNA repair
recombination
genomics
virus
viability
mammal

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Ku regulates the non-homologous end joining pathway choice of DNA double-strand break repair in human somatic cells. / Fattaha, Farjana; Lee, Eu Han; Weisenselb, Natalie; Wang, Yongbao; Lichter, Natalie; Hendrickson, Eric A.

In: PLoS genetics, Vol. 6, No. 2, e1000855, 01.02.2010.

Research output: Contribution to journalArticle

Fattaha, Farjana ; Lee, Eu Han ; Weisenselb, Natalie ; Wang, Yongbao ; Lichter, Natalie ; Hendrickson, Eric A. / Ku regulates the non-homologous end joining pathway choice of DNA double-strand break repair in human somatic cells. In: PLoS genetics. 2010 ; Vol. 6, No. 2.
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