Abstract:In the present study, full-length complementary DNA (cDNA) of Drosha and Exportin 5 involved in the pathway of microRNA (miRNA) biogenesis of the swimming crab Portunus trituberculatus were cloned by rapid amplification of cDNA ends (RACEs). The length of the Drosha gene is 3443 bp, which is predicted to encode a polypeptide of 1038 amino acids, containing two ribonuclease (RNase) Ⅲ domains (RⅢDa and RⅢDb) and a double-stranded RNA binding domain (dsRBD). The full-length of Exportin 5 is 5000 bp, which is predicted to encode a polypeptide of 1208 amino acids, containing an importin-β N-terminal domain (IBN-N) and an exportin 1-like domain (XPO-1). Homology analysis revealed that Drosha in P. trituberculatus is highly similar to those in some species and shares the highest similarity with that in Marsupenaeus japonicus (94%). Quantitative real-time PCR (qRT-PCR) analysis showed that Drosha and Exportin 5 are expressed in all the tested tissues, and were highly expressed in the ovary and hepatopancreas tissues (P<0.05). At different stages of testis development, the expression of the genes Drosha and Exportin 5 shared the same trend, and both showed the highest expression at stage Ⅱ. During ovarian development, the expression level of the genes Drosha and Exportin 5 increased gradually from phase Ⅱ to phase Ⅴ. The results suggest that the genes Drosha and Exportin 5 cooperatively regulate the gonadal development of P. trituberculatus in an miRNA-dependent manner. Furthermore, the results provide useful information for studies on the regulation of gonadal development in P. trituberculatus.
