ITRAQ-based analysis of 17β-estradiol induced proteome in Chinese tongue sole Cynoglossus semilaevis

Abstract

The phenomenon of sex dimorphism prevails among many fish species. It has attracted the general research interest due to its close relationship to fish growth and thus aquaculture productivity. In Chinese tongue sole (Cynoglossus semilaevis), 17β-estradiol (E2) can be used reportedly to induce the feminization of fish, although the detailed regulatory network remained elusive. We treated the tongue sole fry before sex differentiation with E2 (10 and 30 µg/L) to identify potential targets of E2 in Chinese tongue sole. The E2 treatment indeed induced genetic male fish sex-reversal to phenotypic female. Using an iTRAQ-based comparative proteomic analysis, 409 proteins that differentially expressed after E2 induction were identified, including 259 up-regulated and 150 down-regulated proteins. Furthermore, 19 differentially expressed proteins identified in the comparative proteomic analysis were selected to assess their transcription and eight of them exhibited the same tendency. Functions of the eight proteins included mainly nucleotide and protein binding. Interestingly, a far upstream element-binding protein 3-like isoform exhibited the significant upregulation both at transcription and translation levels after E2 treatment. This work identified a set of candidate proteins for E2 response and deepened our understanding of E2 regulatory mechanism.