普遍认为“冷休克”精子受精率低的原因是精子在冷却过程中发生“低温获能样变化”。低温获能精子不需要初始的孵育而获得受精能力，快速经历顶体反应，在雌性生殖道表现为短暂。真获能与低温获能精子间有许多相似之处，但真获能精子能正常受精，而低温获能样变化精子丧失受精能力，产生这种差异的分子机制尚不清楚。研究显示，泛素-蛋白酶体系统（UPS）在精子获能、顶体胞吐以及精子入卵期间可能发挥重要作用。我们对顶体蛋白酶抑制剂（AI）和透明带3（ZP3）蛋白泛素化修饰和功能进行了初步研究，但对AI 和ZP3精子受体失活机制尚不清楚，也未见UPS依赖性的真获能和低温获能样变化精子AI 和ZP3精子受体失活机制方面的研究报道。本研究的主要目的是探究UPS依赖性的AI 和ZP3精子受体失活机制，阐明低温获能样变化精子过早激活的分子机制并采取有效措施有针对性的预防。项目的完成将为更有效保存动物种质资源以及提高繁殖效率提供可靠安全保障。

It is generally believed that the reason of the low fertilization rate for cold shocked sperm of sperm in cold shock is due to cryocapacitation-like changes during cooling process. Cryocapacitation sperm does not need initial incubation to obtain fertility, and undergoes acrosome reaction quickly，it is short-lived in female reproductive tract. There are many similarities between true capacitation and cryocapacitation sperm, but true capacitation sperm can fertilize normally, while cryocapacitation sperm loses fertilization ability. The molecular mechanism of this difference is still unclear.Studies have shown that ubiquitin-proteasome system (UPS) may play an important role in sperm capacitation, acrosome exocytosis and sperm penetration. Ubiquitination and function of acrosin inhibitor (AI) and zona pellucida 3 (ZP3) proteins have been preliminarily studied. However, the deactivation mechanism of sperm receptor ZP3 and AI is still unclear, and there are no reports on the deactivation mechanisms of UPS-dependent true capacitation and cryocapacitation sperm of AI and sperm receptor ZP3. The main purpose of this study is to explore the deactivation mechanism of UPS-dependent sperm receptor ZP3 and AI , clarify the molecular mechanism of premature activation of cryocapacitation sperm and take effective measures to prevent these changes. The completion of the project will provide a theoretical basis for reducing cryocapacitation sperm occurence, it also provides reliable guarantee for effective cryopreservation of Animal Germplasm Resources and improvement of reproductive efficiency.