MEPS 257:87-97 (2003)  -  doi:10.3354/meps257087

Metallothionein genes in the European flat oyster Ostrea edulis: a potential ecological tool for environmental monitoring?

Arnaud Tanguy1,2, Isabelle Boutet2, Ricardo Riso3, Pierre Boudry4, Michel Auffret2, Dario Moraga2,*

1Haskin Shellfish Research Laboratory, 6959 Miller Avenue, Port Norris, New Jersey 08349, USA
2Laboratoire des Sciences de l¹Environnement Marin (LEMAR), UMR CNRS 6539, Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, Technopôle Brest, Iroise, Place Nicolas Copernic, 29280 Plouzané, France
3Laboratoire de Chimie Marine UBO et UPR CNRS 9042 (Roscoff), Institut Universitaire Européen de la Mer, Place Nicolas Copernic, 29280 Plouzané, France
4Laboratoire de Génétique et Pathologie, IFREMER La Tremblade, 17390 La Tremblade, France
*Corresponding author. Email:

ABSTRACT: Metallothioneins (MTs) are small essential proteins involved in cellular processes of metal handling and detoxification. Here, we describe the structure of 2 MT genes in a marine mollusc, the European flat oyster Ostrea edulis. The sequences of these 2 genes code for 2 proteins of 74 and 71 amino acids, respectively, with the 71 amino acid protein having an abnormal lack of cysteine residues. The direct quantification of metal ions bound to purified recombinant proteins demonstrated that the metal-binding capacity of the 2 proteins differs by about 20%. An enzyme-linked immunosorbent assay (ELISA) test, used to quantify MT protein expression in O. edulis exposed to metal under laboratory conditions, showed no significant induction of MTs, either in the gills or the digestive gland despite an increase in metal concentration observed in the same tissues. Similar results were observed with an MT-RNA expression study. These results seem to indicate a low involvement of MTs in metal detoxification in O. edulis. Examination of polymorphism in the coding sequence of OeMT (O. edulis metallothionein) genes by single-strand conformation polymorphism (SSCP) revealed a lack of genetic diversity in field populations.

KEY WORDS: Metallothionein · Detoxification · Expression · ELISA · Polymorphism · Ostrea edulis

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