促性腺激素及其受体调控石斑鱼性逆转的功能研究

The groupers are important aquaculture species in southern China. As a typical protogynous hermaphrodite, some individuals of the groupers can undergo a female-to-male sex change in their life cycle. It was well known that the reproduction activities of teleost were mainly controlled by the hypothalamic-pituitary-gonadal axis (HPG axis). Gonadotropins (GtH), a critical component of HPG axis, play key roles in the regulation of gonadal steroidogenesis, but their roles and underlying mechanisms in regulating sex change in the protogynous hermaphrodite fishes remain unstudied. Trying to reveal the function and molecular mechanisms of GtHs in regulating the sex change of the groupers, using the orange-spotted grouper as a model, this project will investigate the expression profiles of GtHs and other steroidogenesis regulators during sex change of the groupers, overexpress GtH genes in vivo to study their functions in sex change, and explore the molecular mechanisms of GtHs regulating gonadal steroidogenesis during sex change of the groupers. This research may help to provide scientific guidance for the innovation of grouper sex control technologies.

石斑鱼是典型的雌雄同体雌性先熟鱼类，部分个体会发生雌转雄性逆转，雌雄性类固醇激素合成的调控是性逆转的关键。大量研究表明，促性腺激素（Gonadotropin，GtH）在性类固醇激素合成调控中发挥关键性作用。但GtH及其受体在石斑鱼性逆转中的作用和分子机制还不清楚。本项目拟以斜带石斑鱼为研究对象，通过基因表达定位研究GtH及其受体在性逆转中的表达变化，在体过表达实验研究不同GtH对性逆转的功能，细胞实验研究不同GtH信号对下游性类固醇激素合成关键基因的转录调控，进而揭示GtH及其受体对斜带石斑鱼性逆转的作用和调控机制。本项目的实施，将有助于全面了解石斑鱼性逆转及调控机制，为石斑鱼性别控制技术的发展提供理论基础。

石斑鱼是典型的雌雄同体雌性先熟鱼类，部分个体会发生雌转雄性逆转，雌雄性类固醇激 素合成的调控是性逆转的关键。大量研究表明，促性腺激素在性类固 醇激素合成调控中发挥关键性作用。项目围绕促性腺激素及受体在斜带石斑鱼性逆转中的功能和可能的调控机制展开研究。我们首先明确了斜带石斑鱼性逆转过程中促性腺激素及性别调控关键基因的表达模式，发现两种促性腺激素中促滤泡激素（FSH）及其受体在性逆转过程中表达显著升高；我们通过毕赤酵母真核表达系统获得了具生物活性的重组FSH蛋白，并通过在体注射实验，明确了FSH可以成功诱导斜带石斑鱼性逆转；我们进一步的研究表明，fsh/fshr信号可以直接调控性类固醇激素合成关键基因cyp19a1、cyp11c1和hsd11b2的活性，影响个体性类固醇激素的合成转变，从而影响性逆转。项目解析促性腺激素及其受体调控斜带石斑鱼性逆转的功能与分子机制，为建立稳定、环保的石斑鱼性别调控技术奠定理论基础。在石斑鱼类繁育中具一定应用前景。