Abstract: Aldehyde oxidases (AO, EC 1.2.3.1) are a group of protease belonging to the large family of molybdo-flavoenyzme (MFE). In order to research the function of these proteases, aldehyde oxidase genes of the silkworm, Bombyx mori (BmAOXs) were identified and analyzed in this study. Eight candidate genes of BmAOXs sharing the conservative domain with aldehyde oxidases from other species were identified based on the silkworm genomic database. Phylogenetic analysis indicated that BmAOXs were clustered into a cluster with AO proteins of other insects. The results of RT-PCR analysis showed that BmAOX1, BmAOX2, BmAOX3 and BmAOX5 were highly tissue-specific; BmAOX4, BmAOX6, BmAOX7 and BmAOX8, however, showed a broad expression profile in different tissues of both pupa and adult, suggesting that they may play important roles in the silkworm metabolism. By Native-PAGE and active staining, five and six active aldehyde oxidases were detected in tissues of pupa and adult of the silkworm, respectively, but they were in different types and activity levels. These results could provide insights into the further functional research on BmAOX gene family.

Key words: Silkworm (Bombyx mori), aldehyde oxidase, gene identification, expression profiling