DNA ligase III and DNA ligase IV carry out genetically distinct forms of end joining in human somatic cells

Sehyun Oh, Adam Harvey, Jacob Zimbric, Yongbao Wang, Thanh Nguyen, Pauline J. Jackson, Eric A. Hendrickson

Research output: Contribution to journalArticle

38 Citations (Scopus)

Abstract

Ku-dependent C-NHEJ (classic non-homologous end joining) is the primary DNA EJing (end joining) repair pathway in mammals. Recently, an additional EJing repair pathway (A-NHEJ; alternative-NHEJ) has been described. Currently, the mechanism of A-NHEJ is obscure although a dependency on LIGIII (DNA ligase III) is often implicated. To test the requirement for LIGIII in A-NHEJ we constructed a LIGIII conditionally-null human cell line using gene targeting. Nuclear EJing activity appeared unaffected by a deficiency in LIGIII as, surprisingly, so were random gene targeting integration events. In contrast, LIGIII was required for mitochondrial function and this defined the gene's essential activity. Human Ku:LIGIII and Ku:LIGIV (DNA ligase IV) double knockout cell lines, however, demonstrated that LIGIII is required for the enhanced A-NHEJ activity that is observed in Ku-deficient cells. Most unexpectedly, however, the majority of EJing events remained LIGIV-dependent. In conclusion, although human LIGIII has an essential function in mitochondrial maintenance, it is dispensable for most types of nuclear DSB repair, except for the A-NHEJ events that are normally suppressed by Ku. Moreover, we describe that a robust Ku-independent, LIGIV-dependent repair pathway exists in human somatic cells.

Original languageEnglish (US)
Pages (from-to)97-110
Number of pages14
JournalDNA Repair
Volume21
DOIs
StatePublished - Sep 2014

Fingerprint

DNA Ligases
Joining
Repair
Gene Targeting
Genes
DNA End-Joining Repair
Cell Line
Null Lymphocytes
Cells
Essential Genes
Mammals
Maintenance
DNA Ligase ATP
DNA

Keywords

  • A-NHEJ
  • C-NHEJ
  • Double-strand break repair
  • Gene targeting
  • Homologous recombination
  • Ku
  • Ligase III
  • Ligase IV
  • Non-homologous end joining

Cite this

DNA ligase III and DNA ligase IV carry out genetically distinct forms of end joining in human somatic cells. / Oh, Sehyun; Harvey, Adam; Zimbric, Jacob; Wang, Yongbao; Nguyen, Thanh; Jackson, Pauline J.; Hendrickson, Eric A.

In: DNA Repair, Vol. 21, 09.2014, p. 97-110.

Research output: Contribution to journalArticle

Oh, Sehyun ; Harvey, Adam ; Zimbric, Jacob ; Wang, Yongbao ; Nguyen, Thanh ; Jackson, Pauline J. ; Hendrickson, Eric A. / DNA ligase III and DNA ligase IV carry out genetically distinct forms of end joining in human somatic cells. In: DNA Repair. 2014 ; Vol. 21. pp. 97-110.
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AU - Harvey, Adam

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AU - Wang, Yongbao

AU - Nguyen, Thanh

AU - Jackson, Pauline J.

AU - Hendrickson, Eric A.

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