Expression Patterns and Gonadotropin Regulation of the TGF-β II Receptor (Bmpr2) during Ovarian Development in the Ricefield Eel .

Bmpr2 plays a central role in the regulation of reproductive development in mammals, but its role during ovarian development in fish is still unclear. To ascertain the function of in ovarian development in the ricefield eel, we isolated and characterized the cDNA sequence; the localization of Bmpr2 protein was determined by immunohistochemical staining; and the expression patterns of in ovarian tissue incubated with FSH and hCG in vitro were analyzed. The full-length cDNA was 3311 bp, with 1061 amino acids encoded. Compared to other tissues, was abundantly expressed in the ovary and highly expressed in the early yolk accumulation (EV) stages of the ovary. In addition, a positive signal for Bmpr2 was detected in the cytoplasm of oocytes in primary growth (PG) and EV stages. In vitro, the expression level of the ligand of , in the 10 ng/mL FSH treatment group was significantly higher after incubation for 4 h than after incubation for different durations. However, expression in the 10 ng/mL FSH treatment group at 2 h, 4 h and 10 h was significantly lower. Importantly, the expression level of and in the 100 IU/mL hCG group had similar changes that were significantly decreased at 4 h and 10 h. In summary, Bmpr2 might play a pivotal role in ovarian growth in the ricefield eel, and these results provide a better understanding of the function of in ovarian development and the basic data for further exploration of the regulatory mechanism of in oocyte development.