Genome-Wide Analysis and Hormone Regulation of Chitin Deacetylases in Silkworm.

Chitin deacetylases (CDAs) are a group of enzymes involved in chitin metabolism in insects; they play a critical role in molting, pupation, and the modification of chitin. In this study, we identified several CDAs in the silkworm, (CDA), and investigated the effect of various hormones on their expression in larvae and embryo cell lines (E). Eight genes encoding CDAs were identified in the silkworm genome. They showed different expression patterns in different tissues, and were classified into three types based on where they were expressed: the exoskeleton, digestive organs, and genital organs. Moreover, we found that some showed upregulated expression during the molting period, especially during the fourth molting period in larvae. We also verified that the expression of was upregulated by treatment with 20-hydroxyecdysone not only in larvae, but also in E cells. Interestingly, juvenile hormone analog treatment also upregulated the expression of some . The overexpression of several transcription factors revealed that the POU transcription factor POUM2 may play a major role in the regulation of expression. Finally, the silencing of and did not lead to abnormal phenotypes or death, but may have led to delays in silkworm pupation. These results provide important information about lepidopteran insects in terms of chitin deacetylases and the regulation of their expression.