Molecular cloning and characterization of a peroxiredoxin gene from the mole cricket, Gryllotalpa orientalis

We report the cloning, expression and characterization of a cDNA encoding the antioxidant enzyme peroxiredoxin (Prx) from the mole cricket, Gryllotalpa orientalis. The G. orientalis Prx (GoPrx) cDNA contains an open reading frame of 660 bp encoding 220 amino acid residues and possesses one cysteine residue that is characteristic of the 1-Cys subgroup of the peroxiredoxin family. The deduced amino acid sequence of the GoPrx cDNA showed 69% identity to Drosophila melanogaster DPx-2540, 50% to D. melanogaster DPx-6005, and 47% to Glossina morsitans morsitans Prx. Phylogenetic analysis further confirmed a closer relationship of the deduced amino acid sequences of the GoPrx gene to the DPx-2540 within the 1-Cys Prx cluster. The cDNA encoding GoPrx was expressed as a 27-kDa polypeptide in baculovirus-infected insect Sf9 cells. The purified recombinant GoPrx was shown to reduce H2O2 in the presence of electrons donated by dithiothreitol, but did not show the activity in the presence of thioredoxin as electron donor. Northern blot analysis revealed the presence of GoPrx transcripts in all tissues examined. When H2O2 was injected into the body cavity of G. orientalis adult, GoPrx mRNA expression was up-regulated in the fat body tissues. Furthermore, the expression levels of GoPrx mRNA in the fat body were particularly high when G. orientalis adult was exposed at low (4 °C) and high (37 °C) temperatures, suggesting that the GoPrx seems to play a protective role against oxidative stress caused by temperature shock.