Cloning of a river pufferfish (Takifugu obscurus) metallothionein cDNA and study of its induction profile in cadmium-exposed fish.
We report here the full-length cDNA sequence of metallothionein (MT) gene from an anadromous river pufferfish, Takifugu obscurus (order: Tetradotiformes; family: Tetradontidae). Phylogenetic relationship analysis revealed that the identified MT has high sequence similarity with many Perciformes fish species. The tissue distribution and concentration- and time-dependent expression of MT mRNA were studied in fish exposed to cadmium. Liver showed the highest level of MT gene expression followed by other tissues (brain, gill and kidney) in response to cadmium exposure. Muscle showed a weak expression response of MT gene. Time-course study revealed highest early phase (at 6h) expression in the brain and late persistence of induction in the intestine. MT mRNA expression showed a concentration-dependent expression in all the tissues. However, induction in brain and liver occurred at much lower concentrations as compared to other tissues. Our results demonstrate that MT in T. obscurus is induced by cadmium exposure which indicates that it plays a functionally conserved function of metal detoxification.
Kim
Jin-Hyoung
JH
Department of Marine Science, College of Natural Sciences, Inha University, Incheon 402-751, South Korea.
Wang
Soon-Young
SY
Kim
Il-Chan
IC
Ki
Jang-Seu
JS
Raisuddin
Sheikh
S
Lee
Jae-Seong
JS
Han
Kyung-Nam
KN
D000222:Adaptation, Physiological / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002104:Cadmium / Q000633:toxicity*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D004784:Environmental Monitoring / Q000379:methods*; D015870:Gene Expression / Q000187:drug effects*; D008668:Metallothionein / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010802:Phylogeny; D020133:Reverse Transcriptase Polymerase Chain Reaction; D045483:Rivers; D017386:Sequence Homology, Amino Acid; D023721:Tetraodontiformes / Q000235:genetics / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D018076:DNA, Complementary; D014874:Water Pollutants, Chemical; D002104:Cadmium; D008668:Metallothionein