Identification, sequencing and expression of selenium-dependent glutathione peroxidase transcript in the freshwater bivalve Unio tumidus exposed to Aroclor 1254.
Glutathione peroxidases (GPx) and glutathione S-transferases (GST) are essential enzymes of the cellular defense system. The aim of this work was the identification of GPx transcript in a freshwater bivalve, Unio tumidus, and the effects of Aroclor 1254 on GPx and pi-class GST (pi-GST) expression pattern. The GPx full-length coding sequence was obtained by reverse transcription PCR using degenerated primers followed by 5' and 3' rapid amplification of cDNA ends. The GPx cDNA encodes a protein of 232 amino acids. The 72nd amino acid corresponds to a selenocysteine encoded by a TGA codon. Residues essential to the enzymatic function are conserved in GPx of U. tumidus. Specific amplifications of the Se-GPx mRNA from U. tumidus were performed on the digestive gland, the excretory system and the gills. Se-GPx expression level is highest in the digestive gland. No induction of the Se-GPx was observed at the transcriptional level in the digestive gland and the excretory system of Aroclor-treated mussels, while an increase of the pi-GST mRNA level was observed in the excretory system.
Doyen
Périne
P
Lab. E.S.E., Ecotoxicité, Santé Environnementale-CNRS UMR 7146, Université de Metz, rue Delestraint, 57070 Metz, France.
Vasseur
Paule
P
Rodius
François
F
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D020111:Chlorodiphenyl (54% Chlorine) / Q000633:toxicity*; D018076:DNA, Complementary / Q000235:genetics; D041981:Gastrointestinal Tract / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D005880:Gills / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000235:genetics* / Q000378:metabolism; D051549:Glutathione S-Transferase pi / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D049881:Unio / Q000235:genetics* / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D018076:DNA, Complementary; D014874:Water Pollutants, Chemical; D020111:Chlorodiphenyl (54% Chlorine); D005979:Glutathione Peroxidase; D051549:Glutathione S-Transferase pi