title: Identification and response to metals of metallothionein in two ancient fishes: white sturgeon (Acipenser transmontanus) and lake sturgeon (Acipenser fulvescens).
abstract: White sturgeon (Acipenser transmontanus) are among the most sensitive species of fishes to Cu, Cd, and Zn, but there is no information about sensitivity of lake sturgeon (Acipenser fulvescens). To begin to elucidate molecular mechanism(s) of sensitivity of sturgeons to metals a cDNA encoding metallothionein (MT) was amplified from livers of white sturgeon (WS-MT) and lake sturgeon (LS-MT), and expression in response to Cu, Cd, or Zn was characterized in liver explants from each species. The primary structure of WS-MT and LS-MT contained 20 cysteine residues, which is the same as MTs of teleost fishes. However, the primary structure of WS-MT and LS-MT contained 63 amino acids, which is longer than any MT identified in teleost fishes. Abundance of transcripts of WS-MT in explants exposed to 0.3, 3, 30, or 100 μg/L of Cu was 1.7-, 1.7-, 2.1-, and 2.6-fold less than in controls, respectively. In contrast, abundances of transcripts of WS-MT were 3.3- and 2.4-fold greater in explants exposed to 30 μg/L of Cd and 1000 μg/L of Zn, respectively. Abundance of transcripts of LS-MT was not significantly different at any concentration of Cu, Cd, or Zn. MT is hypothesized to represent a critical mechanism for detoxification of metals. Therefore, results of this study suggest that sensitivity of sturgeons to exposure to Cu, Cd, or Zn might be a result of the relatively lesser maximal response of MT to metals. The study also suggestslake sturgeon might be more sensitive than white sturgeon to metals.
authors: Toxicology Centre, University of Saskatchewan, Saskatoon, SK, Canada; Toxicology Graduate Program, University of Saskatchewan, Saskatoon, SK, Canada.
authors: Jon A
authors: JA
authors: Doering
authors: Toxicology Centre, University of Saskatchewan, Saskatoon, SK, Canada; Toxicology Graduate Program, University of Saskatchewan, Saskatoon, SK, Canada.
authors: Shawn C
authors: SC
authors: Beitel
authors: Toxicology Centre, University of Saskatchewan, Saskatoon, SK, Canada.
authors: Bryanna K
authors: BK
authors: Eisner
authors: Institute for Environmental Research, RWTH University, Aachen, Germany.
authors: Timon
authors: T
authors: Heide
authors: Institute for Environmental Research, RWTH University, Aachen, Germany.
authors: Henner
authors: H
authors: Hollert
authors: Toxicology Centre, University of Saskatchewan, Saskatoon, SK, Canada; Department of Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, SK, Canada; Department of Biology and Chemistry, State Key Laboratory for Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong, China; School of Biological Science, University of Hong Kong, Hong Kong, China.
authors: John P
authors: JP
authors: Giesy
authors: Toxicology Centre, University of Saskatchewan, Saskatoon, SK, Canada; School of the Environment and Sustainability, University of Saskatchewan, Saskatoon, SK, Canada. Electronic address: markus.hecker@usask.ca.
authors: Markus
authors: M
authors: Hecker
authors: Toxicology Centre, University of Saskatchewan, Saskatoon, SK, Canada.
authors: Steve B
authors: SB
authors: Wiseman
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017756:Aquaculture; D001483:Base Sequence; D001955:British Columbia; D002104:Cadmium / Q000633:toxicity; D003300:Copper / Q000633:toxicity; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005399:Fishes / Q000254:growth & development; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects*; D008099:Liver / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D008668:Metallothionein / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019216:Metals, Heavy / Q000633:toxicity*; D008969:Molecular Sequence Data; D009924:Organ Culture Techniques / Q000662:veterinary; D009994:Osmolar Concentration; D010802:Phylogeny; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D016415:Sequence Alignment; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D014922:Wisconsin; D015032:Zinc / Q000633:toxicity
chemical_list: D029941:Fish Proteins; D019216:Metals, Heavy; D011994:Recombinant Proteins; D014874:Water Pollutants, Chemical; D002104:Cadmium; D003300:Copper; D008668:Metallothionein; D015032:Zinc
keywords: Cadmium; Copper; Fish; In vitro; Liver; Zinc