title: Breast cancer 1 (BRCA1)-deficient embryos develop normally but are more susceptible to ethanol-initiated DNA damage and embryopathies.
abstract: The breast cancer 1 (brca1) gene is associated with breast and ovarian cancers, and heterozygous (+/-) brca1 knockout progeny develop normally, suggesting a negligible developmental impact. However, our results show BRCA1 plays a broader biological role in protecting the embryo from oxidative stress. Sox2-promoted Cre-expressing hemizygous males were mated with floxed brca1 females, and gestational day 8 +/- brca1 conditional knockout embryos with a 28% reduction in protein expression were exposed in culture to the reactive oxygen species (ROS)-initiating drug ethanol (EtOH). Untreated +/- brca1-deficient embryos developed normally, but when exposed to EtOH exhibited increased levels of oxidatively damaged DNA, measured as 8-oxo-2'-deoxyguanosine, γH2AX, which is a marker of DNA double strand breaks that can result from 8-oxo-2'-deoxyguanosine, formation, and embryopathies at EtOH concentrations that did not affect their brca1-normal littermates. These results reveal that even modest BRCA1 deficiencies render the embryo more susceptible to drug-enhanced ROS formation, and corroborate a role for DNA oxidation in the mechanism of EtOH teratogenesis.
authors.affiliation: Department of Pharmaceutical Sciences, Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Shapiro
authors.affiliation: Department of Pharmacology and Toxicology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Lutfiya
authors.initials: L
authors.lastname: Miller-Pinsler
authors.affiliation: Department of Pharmaceutical Sciences, Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada; Department of Pharmacology and Toxicology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada. Electronic address: pg.wells@utoronto.ca.
authors.forename: Peter G
authors.initials: PG
authors.lastname: Wells
mesh_terms: D000818:Animals; D019313:BRCA1 Protein; D004249:DNA Damage; D047108:Embryonic Development / Q000187:drug effects; D000431:Ethanol / Q000009:adverse effects*; D005260:Female; D008297:Male; D051379:Mice; D018384:Oxidative Stress; D055748:SOXB1 Transcription Factors / Q000378:metabolism*; D064793:Teratogenesis; D025521:Tumor Suppressor Proteins / Q000172:deficiency*
chemical_list: D019313:BRCA1 Protein; C000605931:Brca1 protein, mouse; D055748:SOXB1 Transcription Factors; C527783:Sox2 protein, mouse; D025521:Tumor Suppressor Proteins; D000431:Ethanol
keywords: Breast cancer 1 (BRCA1); DNA repair; Embryo culture; Embryopathies; Ethanol; Oxidatively damaged DNA