Related Experiment Video

Updated: Mar 1, 2026

Identifying the Effects of BRCA1 Mutations on Homologous Recombination using Cells that Express Endogenous Wild-type BRCA1
08:53

Identifying the Effects of BRCA1 Mutations on Homologous Recombination using Cells that Express Endogenous Wild-type BRCA1

Published on: February 17, 2011

15.1K

A Class of Environmental and Endogenous Toxins Induces BRCA2 Haploinsufficiency and Genome Instability

Shawn Lu Wen Tan1, Saakshi Chadha1, Yansheng Liu2

  • 1Medical Research Council Cancer Unit, University of Cambridge, Hills Road, Cambridge CB2 0XZ, UK.

Cell
|June 3, 2017
PubMed

Insights

Environmental toxins like formaldehyde can trigger cancer in individuals with BRCA2 mutations by destabilizing DNA replication. This highlights a public health risk from common aldehydes.

Area of Science:

  • Genetics
  • Environmental Health
  • Molecular Biology

Background:

  • Mutations in the BRCA2 tumor suppressor gene increase cancer susceptibility.
  • Formaldehyde is a common environmental toxin and cellular metabolite.
  • BRCA2 deficiency impairs DNA repair mechanisms, particularly homologous recombination.

Purpose of the Study:

  • To investigate the impact of formaldehyde on DNA replication forks in cells with heterozygous BRCA2 mutations.
  • To elucidate the mechanism by which formaldehyde affects BRCA2 expression and function.
  • To explore the role of RNA-DNA hybrids (R-loops) in aldehyde-induced genomic instability.

Main Methods:

  • Cellular assays to assess DNA replication fork stability and chromosomal aberrations.
  • Proteasomal degradation assays to determine BRCA2 protein levels.
  • Experiments using Ribonuclease H1 to evaluate the role of R-loops.

Main Results:

  • Formaldehyde stalls and destabilizes DNA replication forks, causing chromosomal aberrations in BRCA2-mutated cells.
  • Formaldehyde selectively depletes BRCA2 protein via proteasomal degradation.
  • Acetaldehyde induces similar effects, and Ribonuclease H1 ameliorates these issues, suggesting R-loop involvement.

Conclusions:

  • Low-level formaldehyde exposure can induce BRCA2 haploinsufficiency, sensitizing carriers to cancer.
  • Aldehyde-induced genomic instability may occur through aberrant R-loops during DNA replication.
  • Environmental and endogenous aldehydes pose a public health risk for BRCA2 mutation carriers.
Keywords:
BRCA2R-loopSWATH-MSacetaldehydealdehydeformaldehydeinduced haploinsufficiencyproteasomal degradationreplication stress

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