cDNA cloning and gene expression of ribosomal S9 protein gene in the mollusk Corbicula fluminea: a new potential biomarker of metal contamination up-regulated by cadmium and repressed by zinc.
Biological indicators can be used to assess polluted sites, but their success depends on their specificity. The aim of the present study was to identify a specific cadmium biomarker of the freshwater bivalve Corbicula fluminea. Differential display technique was used to identify new molecular indicators for cadmium exposure. Gene expression of C. fluminea transplanted into a cadmium- and zinc-contaminated river was compared to gene expression of bivalves from a reference site. One differentially expressed band was identified, and the entire cDNA sequence coding for the ribosomal protein S9 (rpS9) was cloned. The rpS9 gene expression was studied by real-time reverse transcription-polymerase chain reaction. After controlled cadmium (15 microg/L) and/or zinc (1 mg/L) laboratory contaminations of the bivalves, this gene was shown to be up-regulated by cadmium and down-regulated by zinc. A 48-d transplantation of animals into a polymetallic field contamination in the Lot river basin (Midi-Pyrénées region, France) showed that rpS9 gene regulation was correlated with the fluctuating cadmium and zinc water contents. To our knowledge, the existence of a gene that is up-regulated by cadmium and repressed by zinc is demonstrated here for the first time.
Achard-Joris
Maud
M
Laboratoire d'Ecophysiologie et d'Ecotoxicologie des Systèmes Aquatiques (LEESA), Universite Bordeaux I/UMR CNRS 5805, Place du Dr. Peyneau, 33120 Arcachon, France.
Gonzalez
Patrice
P
Marie
Véronique
V
Baudrimont
Magalie
M
Bourdineaud
Jean-Paul
JP
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015415:Biomarkers; D002104:Cadmium / Q000633:toxicity*; D003001:Cloning, Molecular; D049874:Corbicula / Q000235:genetics* / Q000502:physiology; D015536:Down-Regulation; D020869:Gene Expression Profiling; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000091243:Ribosomal Protein S9; D012269:Ribosomal Proteins / Q000096:biosynthesis*; D012680:Sensitivity and Specificity; D015854:Up-Regulation / Q000187:drug effects; D015032:Zinc / Q000633:toxicity*
D015415:Biomarkers; D000091243:Ribosomal Protein S9; D012269:Ribosomal Proteins; D002104:Cadmium; D015032:Zinc