title: Three novel superoxide dismutase genes identified in the marine polychaete Perinereis nuntia and their differential responses to single and combined metal exposures.
abstract: To identify superoxide dismutase (SOD) genes and evaluate their usefulness as potential markers for monitoring metal toxicity in aquatic environment, we cloned, sequenced, and characterized 3 SOD genes (Cu/Zn-SOD1, Cu/Zn-SOD2, and Mn-SOD) from the marine polychaete Perinereis nuntia. The accumulated metal contents and expressions of 3 SOD genes were compared after exposure to single and combinations of heavy metals, As, Ni, and Pb. The deduced amino acid sequences of the 3 SODs had evolutionary conserved domains, such as metal binding sites, and signature sequences. The phylogenetic analysis revealed that Cu/Zn-SOD1, Cu/Zn-SOD2, and Mn-SOD were clustered with extracellular Cu/Zn-SOD, intracellular Cu/Zn-SOD and mitochondrial Mn-SOD, respectively, of other species. The accumulated contents of Ni and Pb increased significantly in a time - dependent manner after exposure to both single and combination of the metals. However, the concentration of As did not change significantly in the exposure test. The quantitative real-time polymerase chain reaction (PCR) array showed that the 3 SOD genes had differential expression patterns depending on the exposure condition. The expression of all SODs mRNAs was significantly elevated in response to Pb alone and in combination with As. The mRNA level of Cu/Zn-SOD1 was the highest after exposure to Pb alone, while that of Mn-SOD was remarkably enhanced after exposure to a combination of As and Pb. Exposure to Ni alone rapidly elevated the expression of Cu/Zn-SOD1 and Mn-SOD mRNA, which then gradually decreased. Exposure to As had no significant effect on the modulation of any of the SOD genes of P. nuntia. These results suggest that all SOD genes might play important roles in cellular protection as antioxidant enzymes against heavy metal toxicity via different modes of action in P. nuntia and might have the potential to act as indicators in an environment containing a mixture of metals.
authors.affiliation: Department of Biological Sciences, Sungkyunkwan University, Suwon 440-746, South Korea.
authors.forename: Eun-Ji
authors.initials: EJ
authors.lastname: Won
authors.affiliation: Marine Environment and Conservation Department, Korea Institute of Ocean Science and Technology (KIOST), Ansan 426-744, South Korea.
authors.forename: Kongtae
authors.initials: K
authors.lastname: Ra
authors.affiliation: Marine Environment and Conservation Department, Korea Institute of Ocean Science and Technology (KIOST), Ansan 426-744, South Korea.
authors.forename: Kyung-Tae
authors.initials: KT
authors.lastname: Kim
authors.affiliation: Department of Biological Sciences, Sungkyunkwan University, Suwon 440-746, South Korea.
authors.forename: Jae-Seong
authors.initials: JS
authors.lastname: Lee
authors.affiliation: Department of Life Science, College of Natural Sciences, Sangmyung University, Seoul 110-743, South Korea. Electronic address: ymlee70@smu.ac.kr.
authors.forename: Young-Mi
authors.initials: YM
authors.lastname: Lee
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001483:Base Sequence; D015415:Biomarkers / Q000378:metabolism; D017753:Ecosystem; D004784:Environmental Monitoring; D000075322:Heavy Metal Poisoning; D008670:Metals / Q000378:metabolism; D019216:Metals, Heavy / Q000032:analysis / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism; D008969:Molecular Sequence Data; D009792:Oceans and Seas; D010802:Phylogeny; D011041:Poisoning / Q000378:metabolism*; D011077:Polychaeta / Q000201:enzymology / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism; D013482:Superoxide Dismutase / Q000235:genetics* / Q000378:metabolism; D014877:Water Pollution, Chemical / Q000032:analysis*
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D008670:Metals; D019216:Metals, Heavy; D012333:RNA, Messenger; D013482:Superoxide Dismutase
keywords: Biomarker; Heavy metal; Polychaete Perinereis nuntia; Superoxide dismutase (SOD)