Title: Analysis of CpG methylation in the killifish CYP1A promoter.

Authors: Timme-Laragy, Alicia R; Meyer, Joel N; Waterland, Robert A; Di Giulio, Richard T

Published In Comp Biochem Physiol C Toxicol Pharmacol, (2005 Aug)

Abstract: Fundulus heteroclitus (Atlantic killifish or mummichog) inhabiting a creosote-contaminated Superfund site on the Elizabeth River (VA, USA), exhibit a lack of induction of cytochrome P4501A (CYP1A) mRNA, immunodetectable protein, and catalytic activity after exposure to typical inducers. This "refractory CYP1A phenotype" is not explained by alterations in mRNA expression of known CYP1A transcription factors. Furthermore, the refractory phenotype is lost progressively during development in laboratory-reared F1 generation fish. Thus, while heritable, the refractory CYP1A phenotype does not appear to be genetically based. To test the hypothesis that cytosine methylation at CpG sites in the promoter region of CYP1A underlies the refractory CYP1A phenotype, we employed bisulfite sequencing to compare the methylation status of CpG sites in the CYP1A promoter region of DNA from killifish from the Elizabeth River and a reference site. We examined genomic DNA both from livers of wild-caught adult killifish and from pools of F1 generation embryos raised in the laboratory. In fish from both the contaminated and the reference site, cytosine methylation was not detectable at any of the 34 CpG sites examined, including 3 that are part of putative xenobiotic response elements.

PubMed ID: 16257583

MeSH Terms: Animals; Base Sequence; CpG Islands*; Cytochrome P-450 CYP1A1/genetics*; DNA Methylation*; Female; Fundulidae/genetics*; Male; Molecular Sequence Data; Promoter Regions (Genetics)*; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't