Abstract
The development of Portunus trituberculatus egg cells is directly related to the nutritional status of the fertilized egg, which affects the key production stages of offspring hatching. Vitellogenin plays a key role in the nutrient supply required for the development of the egg cells. The c-Jun N-terminal kinase (JNK) is an important member of the mitogen-activated protein kinase (MAPK) superfamily and plays an important role in cell proliferation, transformation, differentiation, and apoptosis. At present, there are no reports on the involvement of the JNK signaling pathway in the reproductive regulation of P. trituberculatus. In this study, rapid amplification of complementary DNA ends amplification technology was used to clone the full length of JNK complementary DNA, which has a length of 2094 bp, including an open reading frame (ORF) of 1266 bp encoding a 421-amino acid protein. The protein includes the S_TKC conserved domain with a TPY phosphorylation site, which is a typical feature of the JNK gene family. Observing tissue sections found the oocytes in the inhibitor group developed slowly, while the oocytes in the activated group showed accelerated development. Meanwhile, Portunus trituberculatus JNK and vitellogenin (Vg) genes exhibited the same trend in the hepatopancreas and ovaries, and the expression of the SP600125 group was downregulated (P < 0.05), while the anisomycin group was upregulated (P < 0.05). In addition, JNK enzyme activity and vitellin (Vn) content in the ovarian tissue showed that the JNK activity of the SP600125 group decreased, while activity increased in the anisomycin group. The accumulation of Vn content in the SP600125 group decreased, and that in the anisomycin group increased. In summary, after injection with inhibitor or activator, the JNK signaling pathway of P. trituberculatus was inhibited or activated, the accumulation of Vn in the ovary was reduced or increased, and ovarian development was inhibited or accelerated, respectively. These results indicated that the JNK signaling pathway is involved in the regulation of Vg synthesis and ovarian development in P. trituberculatus. The results of this study further add to the knowledge of the breeding biology of P. trituberculatus and provide a theoretical reference for the optimization of breeding techniques in aquaculture production systems.