title: Hepatic transcriptional responses to copper in the three-spined stickleback are affected by their pollution exposure history.
abstract: Some fish populations inhabiting contaminated environments show evidence of increased chemical tolerance, however the mechanisms contributing to this tolerance, and whether this is heritable, are poorly understood. We investigated the responses of two populations of wild three-spined stickleback (Gasterosteus aculeatus) with different histories of contaminant exposure to an oestrogen and copper, two widespread aquatic pollutants. Male stickleback originating from two sites, the River Aire, with a history of complex pollution discharges, and Siblyback Lake, with a history of metal contamination, were depurated and then exposed to copper (46μg/L) and the synthetic oestrogen ethinyloestradiol (22ng/L). The hepatic transcriptomic response was compared between the two populations and to a reference population with no known history of exposure (Houghton Springs, Dorset). Gene responses included those typical for both copper and oestrogen, with no discernable difference in response to oestrogen between populations. There was, however, some difference in the magnitude of response to copper between populations. Siblyback fish showed an elevated baseline transcription of genes encoding metallothioneins and a lower level of metallothionein induction following copper exposure, compared to those from the River Aire. Similarly, a further experiment with an F1 generation of Siblyback fish bred in the laboratory found evidence for elevated transcription of genes encoding metallothioneins in unexposed fish, together with an altered transcriptional response to 125μg/L copper, compared with F1 fish originating from the clean reference population exposed to the same copper concentration. These data suggest that the stickleback from Siblyback Lake have a differential response to copper, which is inherited by the F1 generation in laboratory conditions, and for which the underlying mechanism may include an elevation of baseline transcription of genes encoding metallothioneins. The genetic and/or epigenetic mechanisms contributing to this inherited alteration of metallothionein transcription have yet to be established.
authors.affiliation: Biosciences, College of Life & Environmental Sciences, University of Exeter, Exeter EX4 4QD, UK; Biosciences, College of Science, Swansea University, Swansea SA2 8PP, UK. Electronic address: T.M.UrenWebster@swansea.ac.uk.
authors.forename: Tamsyn M
authors.initials: TM
authors.lastname: Uren Webster
authors.affiliation: School of Biosciences, The University of Birmingham, Birmingham B15 2TT, UK.
authors.forename: Tim D
authors.initials: TD
authors.lastname: Williams
authors.affiliation: Centre for Environment, Fisheries and Aquaculture Science, Cefas Weymouth Laboratory, Weymouth DT4 8UB, UK.
authors.forename: Ioanna
authors.initials: I
authors.lastname: Katsiadaki
authors.affiliation: Biosciences, College of Life & Environmental Sciences, University of Exeter, Exeter EX4 4QD, UK.
authors.forename: Anke
authors.initials: A
authors.lastname: Lange
authors.affiliation: Biosciences, College of Life & Environmental Sciences, University of Exeter, Exeter EX4 4QD, UK.
authors.forename: Ceri
authors.initials: C
authors.lastname: Lewis
authors.affiliation: Biosciences, College of Life & Environmental Sciences, University of Exeter, Exeter EX4 4QD, UK.
authors.forename: Janice A
authors.initials: JA
authors.lastname: Shears
authors.affiliation: Biosciences, College of Life & Environmental Sciences, University of Exeter, Exeter EX4 4QD, UK.
authors.forename: Charles R
authors.initials: CR
authors.lastname: Tyler
authors.affiliation: Biosciences, College of Life & Environmental Sciences, University of Exeter, Exeter EX4 4QD, UK. Electronic address: E.Santos@exeter.ac.uk.
authors.forename: Eduarda M
authors.initials: EM
authors.lastname: Santos
mesh_terms: D000818:Animals; D003300:Copper / Q000633:toxicity*; D004997:Ethinyl Estradiol / Q000633:toxicity; D005786:Gene Expression Regulation / Q000187:drug effects*; D060106:Lakes; D008099:Liver / Q000187:drug effects*; D008297:Male; D008668:Metallothionein / Q000235:genetics; D045483:Rivers; D023701:Smegmamorpha / Q000502:physiology*; D014874:Water Pollutants, Chemical / Q000633:toxicity
chemical_list: D014874:Water Pollutants, Chemical; D004997:Ethinyl Estradiol; D003300:Copper; D008668:Metallothionein
keywords: Adaptation; Freshwater; Metals; Pollution; Teleost