Molecular characterization of glutaredoxin 2 from Ostrinia furnacalis

Glutaredoxins (GRXs) play very important roles in maintaining intracellular redox homeostasis. In the present study, the full-length cDNA sequence encoding GRX2, named OfurGRX2 (GenBank accession no. GU393246), was obtained from Ostrinia furnacalis, using reverse transcription polymerase chain reaction and rapid amplification of cDNA ends. Sequence analysis revealed that the open reading frame of OfurGRX2 consists of 351 nucleotides encoding 116 amino acid residues with a predicted molecular weight of 12.6 kDa. Homolog research revealed that OfurGRX2 shares a common active site, CPYC/CPFC, with other insect counterparts. Expression profiles revealed that OfurGRX2 is a ubiquitous gene expressed in insect heads, fat bodies, epidermises, mid guts and muscles. The OfurGRX2 transcript peaked in 36-h larvae of 4th instars, and then suddenly declined in the molting stage. Hormone treatment experiments revealed that 20-hydroxyecodyson (20e) significantly induces the expression of the OfurGRX2 transcript, whereas juvenile hormone (JH) counteracts 20e effects. Adverse stress factors (including starvation, ultraviolet light, mechanical injury, Escherichia coli exposure, and high and low temperatures) dramatically induced OfurGRXGRX2 transcript expression, which confirmed for the first time that GRX2 play important roles in insecta during exposure to adverse environments.