Heavy metal-induced differential gene expression of metallothionein in Javanese medaka, Oryzias javanicus.
A metallothionein (MT) gene was isolated for the first time from Javanese medaka, Oryzias javanicus, which shows high adaptability from freshwater to seawater. The full-length cDNA of MT from O. javanicus (OjaMT) comprises 349 bp, excluding the poly(A)+ stretch, and codes for a total of 60 amino acids. The positions of cysteine residues are highly conserved. The pattern of OjaMT expression induced by six heavy metals was analyzed via real-time quantitative polymerase chain reaction (PCR). The level of hepatic OjaMT mRNA was increased in a dose-dependent manner by Ag, Cd, Cu, and Zn after 24 h of exposure. However, after Cr and Ni exposure, a significant decrease in OjaMT levels was observed. Cadmium-induced OjaMT expression was detectable in fishes as young as 3 months. After Cd exposure, OjaMT induction was prominent in intestine and liver and moderate in muscle and gill. OjaMT mRNA levels could represent a good biomarker for monitoring heavy metals in seawater.
Woo
Seonock
S
Southern Coastal Environment Research Division, Korea Ocean Research and Development Institute, Geoje, 656-830, Korea.
Yum
Seungshic
S
Jung
Jee Hyun
JH
Shim
Won Joon
WJ
Lee
Chang-Hoon
CH
Lee
Taek-Kyun
TK
D000375:Aging; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects*; D005819:Genetic Markers; D008668:Metallothionein / Q000235:genetics / Q000378:metabolism*; D019216:Metals, Heavy / Q000494:pharmacology*; D008969:Molecular Sequence Data; D009990:Oryzias / Q000378:metabolism*; D016133:Polymerase Chain Reaction / Q000379:methods; D014018:Tissue Distribution
D018076:DNA, Complementary; D029941:Fish Proteins; D005819:Genetic Markers; D019216:Metals, Heavy; D008668:Metallothionein