Loss of BRCA1 or BRCA2 markedly increases the rate of base substitution mutagenesis and has distinct effects on genomic deletions

J. Zámborszky, B. Szikriszt, J. Z. Gervai, O. Pipek, Póti, M. Krzystanek, D. Ribli, J. M. Szalai-Gindl, I. Csabai, Z. Szallasi, C. Swanton, A. L. Richardson, D. Szüts

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

Loss-of-function mutations in the BRCA1 and BRCA2 genes increase the risk of cancer. Owing to their function in homologous recombination repair, much research has focused on the unstable genomic phenotype of BRCA1/2 mutant cells manifest mainly as large-scale rearrangements. We used whole-genome sequencing of multiple isogenic chicken DT40 cell clones to precisely determine the consequences of BRCA1/2 loss on all types of genomic mutagenesis. Spontaneous base substitution mutation rates increased sevenfold upon the disruption of either BRCA1 or BRCA2, and the arising mutation spectra showed strong and specific correlation with a mutation signature associated with BRCA1/2 mutant tumours. To model endogenous alkylating damage, we determined the mutation spectrum caused by methyl methanesulfonate (MMS), and showed that MMS also induces more base substitution mutations in BRCA1/2-deficient cells. Spontaneously arising and MMS-induced insertion/deletion mutations and large rearrangements were also more common in BRCA1/2 mutant cells compared with the wild-type control. A difference in the short deletion phenotypes of BRCA1 and BRCA2 suggested distinct roles for the two proteins in the processing of DNA lesions, as BRCA2 mutants contained more short deletions, with a wider size distribution, which frequently showed microhomology near the breakpoints resembling repair by non-homologous end joining. An increased and prolonged gamma-H2AX signal in MMS-treated BRCA1/2 cells suggested an aberrant processing of stalled replication forks as the cause of increased mutagenesis. The high rate of base substitution mutagenesis demonstrated by our experiments is likely to significantly contribute to the oncogenic effect of the inactivation of BRCA1 or BRCA2.Oncogene advance online publication, 25 July 2016; doi:10.1038/onc.2016.243.

Original languageEnglish
JournalOncogene
DOIs
Publication statusAccepted/In press - Jul 25 2016

Fingerprint

Methyl Methanesulfonate
Mutagenesis
Mutation
INDEL Mutation
BRCA2 Gene
BRCA1 Gene
Phenotype
Recombinational DNA Repair
Mutation Rate
Oncogenes
Publications
Chickens
Neoplasms
Clone Cells
Genome
DNA
Research
Proteins

ASJC Scopus subject areas

  • Molecular Biology
  • Cancer Research
  • Genetics

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Loss of BRCA1 or BRCA2 markedly increases the rate of base substitution mutagenesis and has distinct effects on genomic deletions. / Zámborszky, J.; Szikriszt, B.; Gervai, J. Z.; Pipek, O.; Póti; Krzystanek, M.; Ribli, D.; Szalai-Gindl, J. M.; Csabai, I.; Szallasi, Z.; Swanton, C.; Richardson, A. L.; Szüts, D.

In: Oncogene, 25.07.2016.

Research output: Contribution to journalArticle

Zámborszky, J, Szikriszt, B, Gervai, JZ, Pipek, O, Póti, Krzystanek, M, Ribli, D, Szalai-Gindl, JM, Csabai, I, Szallasi, Z, Swanton, C, Richardson, AL & Szüts, D 2016, 'Loss of BRCA1 or BRCA2 markedly increases the rate of base substitution mutagenesis and has distinct effects on genomic deletions', Oncogene. https://doi.org/10.1038/onc.2016.243
Zámborszky, J. ; Szikriszt, B. ; Gervai, J. Z. ; Pipek, O. ; Póti ; Krzystanek, M. ; Ribli, D. ; Szalai-Gindl, J. M. ; Csabai, I. ; Szallasi, Z. ; Swanton, C. ; Richardson, A. L. ; Szüts, D. / Loss of BRCA1 or BRCA2 markedly increases the rate of base substitution mutagenesis and has distinct effects on genomic deletions. In: Oncogene. 2016.
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