Objective: 

Glutathione peroxidase (GPX, EC 1.11.1.9) is a family of metalloenzymes that catalyze the detoxification of hydrogen peroxide, using glutathione as reducing factor, and is one of the most important antioxidant enzymes involved in antioxidant homeostatic control. For their ubiquitous distribution, those proteins are well suited for molecular evolution studies, especially in animals adapted to peculiar environments.

Despite numerous previous studies on GPX from aquatic animals, the gene structure and expression of teleost GPXs have not been comprehensively studied. In particular, very little is known about the GPX of Antarctic teleost. The Antarctic species have an interesting evolutionary history because they have developed some adaptations that allow them to survive and to breed in waters where the temperature, oxygen and salt concentration deviate significantly from the average recorded in the temperate waters. They represent paradigmatic cases for adaptation to different temperatures and salinities in their environment.

Methods: 

Specimens of Gymnodraco acuticeps, a teleost fish widely distributed in Antarctic Ocean, were sampled in the Ross Sea (Terra Nova Bay, 74°42'S, 164°7'E) during the XVII Italian Antarctic Expedition. cDNA sequence of Se-GPX has been obtained from hepatic tissue by a combination of RT-PCR, 3' and 5'RACE techniques.

Results: 

The obtained nucleotide sequence and the deduced amino acid sequence have been compared with those of homologous genes already available in Genbank and have been used for phylogenetic analyses. Preliminary results were also obtained regarding the regulation of gene expression.

Conclusions: 

The obtained results represent the stat-up for further studies on physiological antioxidant responses to the Antarctic environment.