Structure-function analysis of the plasma protein fetuin-B

血浆胎球蛋白-B是卵母细胞受精所必需的。胎球蛋白-B是一种有效的蛋白水解酶的抑制物，可预防卵母细胞成熟过程中的早熟反应。因此，胎球蛋白-B可以维持卵母细胞的受精性。在没有抑制剂的情况下，奥伐他星可裂解卵透明带蛋白ZP2，从而介导卵母细胞细胞外基质的主要结构变化。这一过程通常被称为透明带“硬化”。透明带硬化后，精子不能与卵母细胞结合、穿透和受精。胎球蛋白-B缺乏的雌性小鼠是完全不育的，因为它们的卵母细胞有一个过早硬化的透明带。在这项研究计划中，我们计划获得关于胎球蛋白-B(抑制剂)和奥伐他星(蛋白酶)之间特定相互作用的机制知识。我们问胎球蛋白-B和奥伐他星之间的相互作用是否只在受精前重要，或者在早期胚胎发育和孵化过程中也是重要的。我们将确定对抑制奥伐他星至关重要的结构特征。这些知识将有助于开发创新的非激素避孕疗法，也将有助于为患有特发性不孕症的妇女制定治疗策略。大约15%的夫妇对孩子的渴望没有得到满足。为了优化辅助生殖治疗，迫切需要新的卵子质量控制参数。我们将研究卵母细胞的纳米压痕，作为一种快速、公正和无损的卵母细胞质量控制方法。

The plasma protein fetuin-B is essential for the fertilization of oocytes. Fetuin-B is a potent inhibitor of the proteinase ovastacin preventing premature activity of ovastacin during oocyte maturation. Thus fetuin-B maintains the fertility of the oocyte. In the absence of the inhibitor ovastacin cleaves zona pellucida protein ZP2 thus mediating major structural changes of the oocyte extracellular matrix. This process is generally known as zona pellucida “hardening”. Following zona pellucida hardening sperm is unable to bind, penetrated and fertilize the oocyte. Fetuin-B deficient female mice are completely infertile, because their oocytes have a prematurely hardened zona pellucida. In this research proposal we plan to gain mechanistic knowledge about the specific interaction between fetuin-B (inhibitor) and ovastacin (proteinase). We ask if the interaction between fetuin-B and ovastacin is only important before fertilization or also during the early embryo development and hatching. We will determine structural features, which are essential for the inhibition of ovastacin. The knowledge will aid the development of innovative non-hormonal contraceptive therapies, and will also help do develop therapeutic strategies for women with idiopathic infertility. About 15% of couples have an unfulfilled desire for a child. To optimize the assisted reproductive therapies, novel parameters for oocyte quality control are highly desirable. We will study nanoindentation of oocyte as a quick, unbiased and non-destructive method for oocyte quality control.