Identification and functional study of calcification-related peptide from the oriental river prawn (Macrobrachium nipponense)

Molting is an essential physiological process that occurs during crustacean development, with cuticle hardening integral to the process. However, little is known about the molecular mechanisms underlying calcification processes in crustaceans. In this study, we cloned a novel calcification-related peptide gene from the cuticle of the oriental river prawn, Macrobrachium nipponense (Mn-CRP), including mRNA and genomic DNA sequences. The full-length Mn-CRP cDNA was 551 bp and encoded 100 amino acids (AAs). The genomic DNA sequence was 1307 bp and consisted of two introns separating three exons. The deduced AA sequence had a typical chitin-binding 4 domain conserved structure. To examine Mn-CRP function, gene expression patterns in different tissues and molting cycle stages were analyzed by quantitative real-time PCR. Mn-CRP expression was significantly higher in the cuticle than in other tissues and at post-molt stages than in other molt cycle stages, where exoskeleton calcification occurred. Furthermore, silenced Mn-CRP expression by RNA interference (RNAi) effectively inhibited molting and slowed M. nipponense growth rates. These data showed Mn-CRP had an important role in M. nipponense exoskeleton calcification. This study laid the foundation for further research on the molecular mechanisms underpinning molting in crustaceans.