Expression and functional analysis of cathepsin L1 in ovarian development of the oriental river prawn, Macrobrachium nipponense

Cathepsin L is an important member of the cysteine protease family and has a central role in the development of ovaries in insects and fish. In this study, we analyzed the characteristics of the cathepsin L1 gene in the female oriental river prawn, Macrobrachium nipponense. The cathepsin L1 cDNA was 1173 bp in length, including a 960 bp open reading frame that encoded 319 amino acids. The cathepsin L1 gene was classified into the cathepsin L group and named Mn-CTS L1 by phylogenetic analysis. qRT-PCR analysis indicated that Mn-CTS L1 was highly expressed in the hepatopancreas and ovaries of female prawns. During the different stages of ovarian development, Mn-CTS L1 expression in the hepatopancreas and ovaries peaked before ovarian maturation. Mn-CTS L1 expression was higher at the post-larval stage of day 15 than at other stages of embryogenesis. In situ hybridization studies revealed that Mn-CTS L1 was localized in the oocyte of the ovary. Injection of Mn-CTS L1 dsRNA significantly reduced Mn-CTS L1 expression and significantly increased the expression of vitellogenin. Changes in the gonad somatic index also confirmed the inhibitory effects of Mn-CTS L1 dsRNA. These results suggest that Mn-CTS L1 has a key role in ovarian development.