Involvement of the JNK signaling pathway in regulating yolk accumulation in the swimming crab, Portunus trituberculatus.

The c-Jun N-terminal kinase (JNK) signaling pathway regulates the development of ovaries and synthesis of vitellogenin (Vg) in the swimming crab Portunus trituberculatus , but the underlying molecular mechanism remains unclear. In this study, we cloned the essential c-fos gene of the JNK signaling pathway using the rapid amplification of complementary DNA end method. The full-length cDNA of c-fos was 2829 bp long and had a 1497 bp open reading frame encoding a 498 amino acid protein and containing a basic leucine zipper domain. After injecting c-jun-double stranded (ds) RNA to silence the JNK signaling pathway target gene c-jun, the expression levels of key JNK signaling pathway genes (c-jun, JNK, Vg, and c-fos) in the hepatopancreas were significantly down-regulated (P < 0.05). In ovarian tissue, the expression levels of c-jun, c-fos, and Vg genes were significantly down-regulated (P < 0.05), but no significant change was detected for JNK gene expression. Hematoxylin-eosin staining indicated that the oocytes in the c-jun-dsRNA group and the Vg-dsRNA group developed slowly, and an enzyme-linked immunosorbent assay confirmed that the accumulation of vitellin in the ovary was significantly reduced by 56% and 52% in the two groups, respectively. Co-immunoprecipitation results showed that c-Jun and c-fos proteins play a regulatory role by forming a heterodimeric transcription factor activator protein 1. These results indicated that the JNK signaling pathway of P. trituberculatus regulated the synthesis of Vg through the transcription factor activator protein 1, thereby regulating the accumulation of yolk. The results of this study provided a theoretical basis and technical guidance for P. trituberculatus production. • Obtain the full-length cDNA and molecular characteristics of the c-fos gene of Portunus trituberculatus. • The interaction between Jun protein and Fos protein of Portunus trituberculatus was identified. • Explored the regulatory effect of JNK protein target gene c-jun/Vg gene silencing on yolk accumulation. [ABSTRACT FROM AUTHOR]