Gender-specific function of melatonin receptor (MTRI) in gonads of red swamp crayfish, Procambarus clarkii

Melatonin receptor (MTR) plays a crucial role in mediating melatonin signaling. Therefore, it is necessary to study functions and characteristics of MTR. In this study, full length cDNA of MTRI in Procambarus clarkii was cloned. The phylogenetic tree revealed that MTRI amino acid sequence of P. clarkii had the closest relationship with Homarus americanus. The temporal and spatial distribution expression results indicated that MTRI was highly expressed in gonadal tissues and eyestalk. RNA interference (RNAi) was used to identify the content of related hormones and the relative expression of genes in gonads of P. clarkii. The results showed that melatonin had an important effect on gonad of P. clarkii. Due to the specificity of the reproductive system in female and male crayfish, the siRNA interference efficiency was different, GIH, GTH, 5-HT and MT showed the opposite trend. Levels decreased in females but increased in males. However, the sex hormones E2 and T decreased, indicating that the silencing of MTRI will hinder gonadal development. This study provides a theoretical basis for further study of the role of melatonin in crustacean gonads.