Signalling pathways and key genes involved in regulation of ovarian development of Sepia esculenta

Abstract

The golden cuttlefish (Sepia esculenta Hoyle) which has one-time reproduction and die after reproduction, what changes have taken place in the ovarian development in the whole life cycle is a very noteworthy issue. In this study, we performed RNA-Seq technology of ovary tissue from female golden cuttlefish collected at three key developmental periods: growth period (IG), spawning period (IS) and post-reproductive death period (IA). Then, we obtained 66.65 Gb of clean data, with Q20 > 96%. Comparison of the transcriptome data for the IG vs. IS, IG vs. IA and IS vs. IA revealed 10,290, 17,107 and 380 differentially expressed genes (DEGs) respectively. Gene ontology (GO) enrichment analysis of DEGs revealed that oxidative phosphorylation, NADH dehydrogenase (ubiquinone) activity, respiratory chain and other GO entries were significantly enriched. Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathway database alignment and annotation revealed that 317 metabolic pathways differed between IG vs. IS, 317 differed between IG vs. IA; and 161 differed between IS vs. IA. Significantly enriched pathways included oxidative phosphorylation, cell cycle, mTOR signalling pathway, AMPK signalling pathway and ubiquitin-mediated proteolytic pathway were associated and interacted, and the post-reproductive death of golden cuttlefish was regulated by a complex signalling network. This study clarified the regulation of transcripts expression in the ovary of golden cuttlefish at different developmental periods, which not only filled the blank of molecular mechanism of cephalopod ovarian development, but also provided research ideas and experimental models for solving the complex biological proposition of post-reproductive death.