中文摘要：

核糖核峻酶4（ribonuclease-4，RNase-4）是核糖核酸酶A超家族成员之一．物种问RNase-4蛋白序列的相似度高达90％，足该超家族中最为保守的成员．RNase-4的核糖核酸酶活性具有独特的尿嘧啶核苷酸底物偏好性，这与其结构紧密相关．RNase-4可以通过降解外源病原体释放的RNA多聚体而发挥宿主防御功能．最新的研究表明，RNase-4呵以促进血管新生、诱导神绎发育，并存应激条件下保护神经细胞存活，进而延缓神经退行性疾病的发生．本文综述’rRNase-4蛋白的分子结构特钲、酶活性与结构的相关性及其生物学功能的研究进展，并展望RNase-4未来的研究方向和临床应刖前景．

英文摘要：

The Ribonuclease-4 （RNase-4） is one member of the ribonuclease A superfamily. RNase-4 displays the highest level of inter-species sequence similarity （approximately 90%） among the whole family, and unique uridine-specificity enzymatic properties, which relates to its three-dimensional （3D） structure. The biological functions of RNase-4 have not been well characterized to documents, although it is possibly associated with host defence by degrading polymeric RNA released from specific pathogens. Recently studies have revealed that RNase-4 protects neuron degeneration diseases through promoting angiogenesis, neurogenesis, and neuronal survival under stress in neurodegeneration diseases. This review summarizes the molecular characterization, three-dimensional structure, enzymatic properties, and biological functions of RNase-4, and gives fresh perspectives on further investigation and clinical application of RNase-4.