Duplex sequencing identifies genomic features that determine susceptibility to benzo(a)pyrene-induced in vivo mutations
- DOI
- Language of the publication
- English
- Date
- 2022-07-28
- Type
- Article
- Author(s)
- LeBlanc, Danielle P.M.
- Meier, Matthew
- Yin Lo, Fang
- Schmidt, Elizabeth
- Valentine III, Charles
- Williams, Andrew
- Salk, Jesse J.
- Yauk, Carole L.
- Marchetti, Francesco
- Publisher
- BMC
Abstract
Exposure to environmental mutagens increases the risk of cancer and genetic disorders. We used Duplex Sequencing (DS), a high-accuracy error-corrected sequencing technology, to analyze mutation induction across twenty 2.4 kb intergenic and genic targets in the bone marrow of MutaMouse males exposed to benzo(a)pyrene (BaP), a widespread environmental pollutant. DS revealed a linear dose-related induction of mutations across all targets with low intra-group variability. Heterochromatic and intergenic regions exhibited the highest mutation frequencies (MF). C:G > A:T transversions at CCA, CCC and GCC trinucleotides were enriched in BaP-exposed mice consistent with the known etiology of BaP mutagenesis. However, GC-content had no effect on mutation susceptibility. A positive correlation was observed between DS and the “gold-standard” transgenic rodent gene mutation assay. Overall, we demonstrate that DS is a promising approach to study in vivo mutagenesis and yields critical insight into the genomic features governing mutation susceptibility, spectrum, and variability across the genome.
Plain language summary
Health Canada (HC) is responsible for protecting Canadians from potential health risks associated with exposure to new and existing chemicals. Exposure to harmful chemicals can cause changes in the genetic code (i.e., DNA mutations) that may lead to cancer and other genetic diseases. The existing “gold-standard” method for determining whether a chemical induces mutations is the transgenic rodent (TGR) assay that uses genetically modified laboratory rodents (eg, MutaMouse). TGR mice contain a bacterial gene in every cell in the body that is used to measure mutations; however, what happens in the bacterial gene may not accurately reflect what occurs in the mouse DNA. For this reason, in collaboration with Twinstrand Biosciences, HC scientists have implemented an advanced Next Generation Sequencing method, namely Duplex Sequencing, to measure mutations in the MutaMouse DNA after exposure to a potent chemical mutagen, benzo(a)pyrene (BaP). The results showed that Duplex Sequencing was as effective as the TGR assay in detecting mutations induced by various doses of BaP. Unlike the traditional TGR assay, Duplex Sequencing generated detailed information on the types of induced DNA mutations and provided further details on how different regions of the MutaMouse DNA responded to BaP exposure. This additional information can be used to better inform regulatory decisions on the risk associated with a particular exposure. Overall, the results of this study demonstrate the utility of Duplex Sequencing to measure chemically-induced mutations and modernize the way chemicals are tested for mutagenicity for regulatory purposes.
Subject
- Health,
- Health and safety