Effect of Ku80 deficiency on mutation frequencies and spectra at a lacZ reporter locus in mouse tissues and cells

Rita A. Busuttil, Denise P. Muñoz, Ana Maria Garcia, Francis Rodier, Woo Ho Kim, Yousin Suh, Paul Hasty, Judith Campisi, Jan Vijg

Research output: Contribution to journalArticle

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Abstract

Non-homologous end joining (NHEJ) is thought to be an important mechanism for preventing the adverse effects of DNA double strand breaks (DSBs) and its absence has been associated with premature aging. To investigate the effect of inactivated NHEJ on spontaneous mutation frequencies and spectra in vivo and in cultured cells, we crossed a Ku80-deficient mouse with mice harboring a lacZ-plasmid-based mutation reporter. We analyzed various organs and tissues, as well as cultured embryonic fibroblasts, for mutations at the lacZ locus. When comparing mutant with wild-type mice, we observed a significantly higher number of genome rearrangements in liver and spleen and a significantly lower number of point mutations in liver and brain. The reduced point mutation frequency was not due to a decrease in small deletion mutations thought to be a hallmark of NHEJ, but could be a consequence of increased cellular responses to unrepaired DSBs. Indeed, we found a substantial increase in persistent 53BP1 and γH2AX DNA damage foci in Ku80-/- as compared to wild-type liver. Treatment of cultured Ku80-deficient or wild-type embryonic fibroblasts, either proliferating or quiescent, with hydrogen peroxide or bleomycin showed no differences in the number or type of induced genome rearrangements. However, after such treatment, Ku80-deficient cells did show an increased number of persistent DNA damage foci. These results indicate that Ku80-dependent repair of DNA damage is predominantly error-free with the effect of alternative more error-prone pathways creating genome rearrangements only detectable after extended periods of time, i.e., in young adult animals. The observed premature aging likely results from a combination of increased cellular senescence and an increased load of stable, genome rearrangements.

Original languageEnglish (US)
Article numbere3458
JournalPLoS One
Volume3
Issue number10
DOIs
StatePublished - Oct 20 2008

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Mutation Rate
Genes
Joining
Genome
DNA damage
Liver
Tissue
DNA Damage
Premature Aging
mutation
loci
genome
DNA
mice
Fibroblasts
point mutation
Point Mutation
liver
fibroblasts
Aging of materials

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

Cite this

Effect of Ku80 deficiency on mutation frequencies and spectra at a lacZ reporter locus in mouse tissues and cells. / Busuttil, Rita A.; Muñoz, Denise P.; Garcia, Ana Maria; Rodier, Francis; Kim, Woo Ho; Suh, Yousin; Hasty, Paul; Campisi, Judith; Vijg, Jan.

In: PLoS One, Vol. 3, No. 10, e3458, 20.10.2008.

Research output: Contribution to journalArticle

Busuttil, Rita A. ; Muñoz, Denise P. ; Garcia, Ana Maria ; Rodier, Francis ; Kim, Woo Ho ; Suh, Yousin ; Hasty, Paul ; Campisi, Judith ; Vijg, Jan. / Effect of Ku80 deficiency on mutation frequencies and spectra at a lacZ reporter locus in mouse tissues and cells. In: PLoS One. 2008 ; Vol. 3, No. 10.
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