RNA interference of Hemolin causes depletion of phenoloxidase activity in Hyalophora cecropia

Melanization is regulated by the prophenoloxidase cascade and functions as a response to intruding microorganisms in invertebrates. When injecting dsRNA of the lepidopteran immune protein hemolin in pupae of Hyalophora cecropia (Lepidoptera: Saturniidae), we observed a significant reduction in phenoloxidase activity after 24 h, but not after 72 h. The link between hemolin and the prophenoloxidase system suggests that hemolin is a pattern recognition protein important for the triggering of the prophenoloxidase cascade in the defence against bacterial infections.