Identification and expression profiles of chitin deacetylase family genes in the Chinese mitten crab, Eriocheir sinensis

Chitin deacetylases (CDAs) are essential enzymes during moulting and play vital roles in the formation and modification of chitin. Five chitin deacetylase genes were first identified and characterized in the Chinese mitten crab, Eriocheir sinensis. The spatiotemporal expression profiles of the identified CDAs (EsCDAs) have been investigated to reveal their critical functions in moulting of the Chinese mitten crab. Phylogenetic and structural analysis showed that EsCDAs were divided into four of five groups based on sequence similarity and the multiple groups with diverse domain architectures suggested that there were distinctive biological functions among multi-gene family of EsCDAs. Each group contained one or more EsCDAs, except group V, and showed different expression patterns in different tissues and developmental stages. EsCDAs were widely distributed in exoskeleton, digestive organs as well as genital organs, and expressed from eggs to juvenile, especially highly in juvenile stage. During the moulting cycle, the expressions of EsCDAs were up-regulated periodically in the post-moult stage and enhanced by eyestalk resection, which indicate that EsCDAs play an important role in the formation and modification of chitin. Our present study provides fundamental information about crustaceans in terms of chitin deacetylases involved in the chitin metabolic pathway during moulting.