title: Effects on specific promoter DNA methylation in zebrafish embryos and larvae following benzo[a]pyrene exposure.
abstract: Benzo[a]pyrene (BaP) is an established carcinogen and reproductive and developmental toxicant. BaP exposure in humans and animals has been linked to infertility and multigenerational health consequences. DNA methylation is the most studied epigenetic mechanism that regulates gene expression, and mapping of methylation patterns has become an important tool for understanding pathologic gene expression events. The goal of this study was to investigate aberrant changes in promoter DNA methylation in zebrafish embryos and larvae following a parental and continued embryonic waterborne BaP exposure. A total of 21 genes known for their role in human diseases were selected to measure percent methylation by multiplex deep sequencing. At 96hpf (hours post fertilization) compared to 3.3hpf, dazl, nqo1, sox3, cyp1b1, and gstp1 had higher methylation percentages while c-fos and cdkn1a had decreased CG methylation. BaP exposure significantly reduced egg production and offspring survival. Moreover, BaP decreased global methylation and altered CG, CHH, and CHG methylation both at 3.3 and 96hpf. CG methylation changed by 10% or more due to BaP in six genes (c-fos, cdkn1a, dazl, nqo1, nrf2, and sox3) at 3.3hpf and in ten genes (c-fos, cyp1b1, dazl, gstp1, mlh1, nqo1, pten, p53, sox2, and sox3) at 96hpf. BaP also induced gene expression of cyp1b1 and gstp1 at 96hpf which were found to be hypermethylated. Further studies are needed to link aberrant CG, CHH, and CHG methylation to heritable epigenetic consequences associated with disease in later life.
authors.affiliation: Department of Pharmacology, University of Mississippi, University, MS 38677, USA.
authors.forename: J
authors.initials: J
authors.lastname: Corrales
authors.affiliation: Department of Pediatrics, University of Florida, Gainesville, FL 32610, USA.
authors.forename: X
authors.initials: X
authors.lastname: Fang
authors.affiliation: Department of Pharmacology, University of Mississippi, University, MS 38677, USA.
authors.forename: C
authors.initials: C
authors.lastname: Thornton
authors.affiliation: Department of Biology, University of Florida, Gainesville, FL 32669, USA.
authors.forename: W
authors.initials: W
authors.lastname: Mei
authors.affiliation: Department of Biology, University of Florida, Gainesville, FL 32669, USA; University of Florida Genetics Institute, Gainesville, FL 32669, USA.
authors.forename: W B
authors.initials: WB
authors.lastname: Barbazuk
authors.affiliation: Genomics Bioinformatics, USDA ARS, Stoneville, MS 38776, USA.
authors.forename: M
authors.initials: M
authors.lastname: Duke
authors.affiliation: Genomics Bioinformatics, USDA ARS, Stoneville, MS 38776, USA.
authors.forename: B E
authors.initials: BE
authors.lastname: Scheffler
authors.affiliation: Department of Pharmacology, University of Mississippi, University, MS 38677, USA. Electronic address: kwillett@olemiss.edu.
authors.forename: K L
authors.initials: KL
authors.lastname: Willett
mesh_terms: D000818:Animals; D001564:Benzo(a)pyrene / Q000633:toxicity*; D019175:DNA Methylation; D004625:Embryo, Nonmammalian / Q000187:drug effects* / Q000378:metabolism; D005260:Female; D007814:Larva / Q000187:drug effects / Q000378:metabolism; D008297:Male; D011401:Promoter Regions, Genetic; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics
chemical_list: D014874:Water Pollutants, Chemical; D001564:Benzo(a)pyrene
keywords: Benzo[a]pyrene; DNA methylation; Embryo; Larvae; Zebrafish