Molecular mechanisms of sexual plasticity during testicular differentiation and development in the medaka, Olyzias latipes

本研究旨在探讨青鳉精巢分化发育过程中体细胞性可塑性的分子机制。在Hd-rR品系XY青鳉中，雌激素处理诱导雌性分化，雌激素暴露于30 dph（孵化后天数）之前的鱼苗。在雌激素诱导XY性逆转过程中，支持细胞表达foxl 2，而生殖细胞支持细胞的雄性分化标志基因gsdf、dmrt 1等表达降低，随后受到抑制。雌激素虽然能诱导成熟鱼的睾丸-卵子分化，但不能诱导XY性逆转（卵巢分化）。雌激素处理的成熟XY鱼中，foxl 2的表达被诱导。然而，雄性分化标记基因的表达并未被完全抑制。这些结果强烈表明，支持细胞的性可塑性是有限的青少年睾丸分化的进展。

This study focuses on the molecular mechanisms of sexual plasticity of testicular somatic cells during testis differentiation and development in the medaka, Olyzias latipes. In XY medaka of Hd-rR strain, estrogen treatment induces the female differentiation when estrogen expose to the fry before 30 dph(days post hatching). During XY sex reversal by estrogen, Sertoli cells showed the expression of foxl2, whereas the expression of male differentiation maker genes of germ-cell supporting cells were decreased and subsequently suppressed, such as gsdf and dmrt1 etc. Although estrogen induced testis-ova differentiation easily in mature fish, XY sex reversal(ovarian differentiation) was not induced. In mature XY fish treated by estrogen, foxl2 expression was induced. However, expression of male differentiation maker genes was not suppressed completely. These results suggest strongly that sexual plasticity of Sertoli cells is limited with the progression of testis differentiation in medaka.