Molecular characterization and enzymatic analysis of juvenile hormone epoxide hydrolase genes in the red flour beetle <i>Tribolium castaneum</i>

Abstract

Juvenile hormone epoxide hydrolases (JHEHs) degrade juvenile hormones (JHs) and are important for JH titre regulation. Here, we report the cloning and analysis of five jheh-related (jheh-r1-r5) genes in the red flour beetle, Tribolium castaneum, a model species for the coleopteran insects. T. castaneum JHEH-r (TcJHEH-r) proteins show high homology to lepidopteran JHEHs and also to human microsomal epoxide hydrolase. In the phylogenetic tree, Tcjheh-rs were clustered, and interestingly, they were also clustered in the genome. Examination of enzymatic activities using recombinant TcJHEH-r proteins showed that TcJHEH-r3 had strong degradation activity for JH III, whereas TcJHEH-r4 had weak activity. The study has yielded significant information that will facilitate further analysis of JHEHs and epoxide hydrolases.