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

本研究旨在研究青竹睾丸分化和发育过程中睾丸体细胞性可塑性的分子机制。在HD-RR品系的XY青竹中，当雌激素在孵化后30天前暴露于幼鱼时，雌激素处理会诱导雌性分化。在雌激素诱导的XY性逆转过程中，支持细胞表达FOXL2，而生殖细胞支持细胞的雄性分化标记物基因如GSDF和dmrt1的表达降低并随后被抑制。在雌激素处理的成熟XY鱼中，FOXL2被诱导表达。然而，雄性分化标记基因的表达并未完全被抑制。这些结果有力地表明，青蛙睾丸分化过程中支持细胞的性可塑性是有限的。

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.