Identification, sequencing and expression of selenium-dependent glutathione peroxidase transcript in the freshwater bivalve Unio tumidus exposed to Aroclor 1254
- 作者：Pé ; rine Doyen ; Paule Vasseur and Franç ; ois Rodius
- 关键词：Freshwater bivalve ; Unio tumidus ; Se-GPx ; Pi-GST ; Coding sequence ; Expression level ; RT-PCR ; RACE-PCR ; Aroclor
- 刊名：Comparative Biochemistry and Physiology ; Part C
- 出版年：2006
- 期刊代码：8_15320456
- 类别：pha
- 出版时间：October 2006
- 卷：144
- 期：2
- 页码：122-129
- 文件大小：1244 K
摘要
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.