Sexually dimorphic expression of foxl2 in the sea urchin (Mesocentrotus nudus).

Sea urchin (Mesocentrotus nudus) is an important economically mariculture species in several Asian countries, and gonads are the sole edible parts for people. In addition to commercial value, it is an excellent model for studying gonadal development, sex determination and sex differentiation. Identify sex-related genes is an effective way to reveal the molecular mechanism of gonadal development. In the present study, the foxl2 homologous gene was identified in M. nudus. Foxl2 is not a maternal factor, and is detected for the first time in two-arm stages. Additionally, the expression of foxl2 in the testis is higher than in the ovaries before gametogenesis and nutritive phagocyte (NP) utilisation. The foxl2 transcripts were specifically enriched in the cytoplasm of germ cells in both the ovary and testis, but their proteins were more concentrated in the area near the oocyte nucleus. Overall, this study contributes to our understanding of the dynamic and sexually dimorphic expression pattern of foxl2 and provide a useful germ cell marker during gametogenesis in sea urchin.