Molecular Cloning of Prophenoloxidase Genes from the Multicolored Asian Lady Bird Beetle, Harmonia axyridis

다국어 초록 (Multilingual Abstract)

The multicolored Asian ladybird beetle, Harmonia axyridis, is a generalist predator of aphids also, shows a high level of phenotype polymorphism in color pattern of elytra. Although, it is not sure about genetic information of color polymorphism, it has been confirmed that this phenomenon comes from their genetic traits. The color of H. axyridis elytra is mainly composed of black and red pigment. Phenoloxidase (PO) plays an important role in many insect physiological functions, i.e. sclerotization and pigmentation of cuticle and melanization of parasites. Following activation, PO catalyses the hydroxylation of tyrosine and subsequent oxidation of phenolic substance into quinines, which are further converted to melanin. However, the molecular bases of H. axyridis color pattern formation are almost unknown but it may be that the different pro-POs have different expression. In this study, total RNA samples from four each color pattern individuals, for example, succinea 1, succinea 2, conspicua and spectabilis was extracted. A cDNA enconding pro-PO was molecular cloned from each color pattern of H. axyridis and its putative amino acid sequence shared homology with pro-PO of other insects. We are pursuing to elucidate that their pro-PO sequence will be similar with those other insect PPO sequence. There are also regions of high sequence similarity, including putative activation site and two copper binding sites.