title: Upregulation of metallothionein and glucose-6-phosphate dehydrogenase expression in silver sea bream, Sparus sarba exposed to sublethal levels of cadmium.
abstract: In this study, the induction of metallothionein (MT) and glucose-6-phosphate dehydrogenase (G6PDH) gene expression in response to exposure to cadmium (Cd(2+)) was investigated in silver sea bream (Sparus sarba) in vivo. In addition, a primary hepatocyte culture has been developed from silver sea bream liver in order to assess the changes in gene expression of MT and G6PDH in hepatocytes directly exposed to Cd(2+) in vitro. The sea bream metallothionein gene was cloned and characterized for the development of real-time PCR assays for quantification of MT transcript abundance. G6PDH gene expression was quantified using a real-time PCR assay developed using sequence information from a previously cloned silver sea bream G6PDH gene. In both in vivo and in vitro experiments, MT mRNA was highly inducible following Cd(2+) treatment. In addition, Cd(2+) exposure caused the upregulation of G6PDH mRNA expression and this suggests the possibility of the involvement of G6PDH in the defense against Cd(2+)-induced oxidative stress in cells. It is likely that the defense system of silver sea bream to Cd(2+) stress includes upregulation of G6PDH in addition to metallothionein.
authors.affiliation: Department of Biology, The Chinese University of Hong Kong, Shatin, NT, Hong Kong SAR, China.
authors.forename: Angel K Y
authors.initials: AK
authors.lastname: Man
authors.forename: Norman Y S
authors.initials: NY
authors.lastname: Woo
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002104:Cadmium / Q000633:toxicity*; D003001:Cloning, Molecular; D005880:Gills / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D005954:Glucosephosphate Dehydrogenase / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D022781:Hepatocytes / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D008668:Metallothionein / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D011897:Random Allocation; D020133:Reverse Transcriptase Polymerase Chain Reaction; D021541:Sea Bream / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D012333:RNA, Messenger; D014874:Water Pollutants, Chemical; D002104:Cadmium; D008668:Metallothionein; D005954:Glucosephosphate Dehydrogenase