2010/759 Peroxiredoxins and glutathione peroxidases in the fertility of Yellowtail Kingfish

By Andrew Scholefield

This study investigated the distribution of the expression of selected members of the peroxiredoxin (Prx) and glutathione peroxidase (GPx) antioxidant enzyme families in YTK (Seriola lalandi), an important finfish aquaculture species in South Australia. The purpose of investigating the expression of these enzymes was to determine if they played a role in male fertility in fish, as both these families play a role in male fertility in mammals and individual members of these protein families were shown to be highly conserved between mammals and fish.

Prx proteins could be detected in YTK and were discovered to be almost ubiquitously expressed in various organs. A specific sub-class of Prx proteins, Prx 4, was detected in abundance in YTK liver and also showed expression in YTK intestine. Further analysis was conducted for the Prx proteins found that two monomeric forms at 22 kDa and 25 kDa could be detected in brain, liver, kidney, testes and gill of a YTK male. Furthermore two monomeric Prx 4 proteins were detected at 25 kDa and 29 kDa in liver and the latter size was also detected in intestine, testes and gill. Since two different sized isoforms are known to occur in male gonad tissue in mammals, these findings indicate that Prx 4 could play a role in male fertility in fish, as is seen in mammals, but is likely to have a more diverse role in fish.