Functional analysis of the cell cycle protein E gene (ccne) in ovarian development of the white ridgetail prawn, Exopalaemon carinicauda

To investigate the function of the cell cycle Cyclin E gene (ccne) in the ovarian development of Exopalaemon carinicauda, the gene was cloned using the RACE technique, and the relative expression of ccne was analyzed in different tissues at different stages of ovarian development. The effect of knocking down the expression of ccne on yolk protein vitellogenin (vg) was also investigated at ovarian developmental stage II using RNAi. The results showed that the full-length cDNA sequence of ccne in E. carinicauda (1692 bp, with a 5′UTR of 127 bp, a 3′UTR of 299 bp, and an ORF of 1266 bp) could encode a total of 421 amino acids, with a predicted protein molecular weight of 48.04 kDa and a theoretical isoelectric point of 6.28. The relative expression of ccne was high during all stages of ovarian development, with the highest expression occurring in stage III. In addition, the phylogenetic tree showed that E. carinicauda and Penaeus monodon were clustered into one branch. Knocking down the ccne expression inhibited the expression of vg, meaning that the expression of ccne and vg were positively correlated. In situ hybridization showed that ccne was abundantly expressed in ova, thus inferring that ccne plays a regulatory role and is involved in nutrient accumulation and transport in the ovaries of E. carinicauda.