The roles of ribosomal protein S3a in ovarian development of Fenneropenaeus merguiensis (De Man)

Abstract

Shrimp ovarian development is a pivotal step for aquaculture in order to maintain broodstocks. The molecular processes in the ovaries of Fenneropenaeus merguiensis De Man during vitellogenesis were investigated. A quantitative real time PCR (Q-PCR) assay showed a high expression of ribosomal protein S3a (RPS3a) in the early stage of ovarian development and a decline in the later stages. Serotonin (5-HT) increased the expression of RPS3a significantly at 4h after incubating with the ovarian explants. A full-length RPS3a was amplified by the RACE technique and expressed in Escherichia coli BL21 (DE3). Western blot analysis showed that the molecular weight of the recombinant histidine (His)-RPS3a was approximately 33kDa. Its function was tested by incubating undeveloped ovarian explants with His-RPS3a. In vitro assays indicated that the His-RPS3a stimulated the expression of shrimp ovarian peritrophin (SOP) and translational controlled tumor protein (TCTP) genes significantly when compared to the untreated ovarian explants. In addition, the SOP and TCTP genes had been previously reported to be highly expressed during the early stages of ovarian development. In addition, FITC-RPS3a was shown to be imported into the ovarian cells. Therefore, RPS3a may act as a stimulator for the development of shrimp ovaries.