鸭坦布苏病毒获得经空气传播能力的分子机制

Since 2010, Outbreaks and rapid spreading of a novel duck Tembusu virus (TMUV) infection in ducks caused significant economic loss in duck industry. As a member of the genus Flavivirus in the family Flaviviridae, DTMUV may be a potential risk to the safety and health of human and other mammals. To date, the transmission mechanism of DTMUV is still unknown. Our previous studies indicated that duck TMUV (FX2010) can infect duck by airborne transmission route. Duck TMUV FX2010 strain is close related to MM1775 strain that isolated from mosquitoes, but the later can not spread by airborne transmission in ducks, Our previous studies have demonstrated that the E gene plays an important role in the airborne transmission of Tembusu virus. To further explore the mechanism of duck TMUV obtaining the ability of airborne transmission, we will construct a series of chimeric viruses based on FX2010 and MM1775 by exchanging different functional domains of their E proteins. To figure out the key E domain in transmission, the airborne transmission of these rescued viruses will be evaluated in ducks. By comparing the critical E gene domain of FX2010 and MM1775, the key amino acids will be located, and their effects on the airborne transmission will be tested. Furthermore, the propagation and receptor binding capacity of the mutant virus will be assessed in vitro. The study will help us to understand the molecular mechanism of duck TMUV obtaining the ability of airborne transmission.

2010年以来，我国新发鸭坦布苏病毒病的爆发和快速传播给养鸭业造成了巨大的经济损失，作为黄病毒属的成员，该病毒也对人类和其他哺乳动物的安全与健康存在潜在威胁。目前鸭坦布苏病毒的传播机制等重大的科学问题还属于空白阶段，我们前期研究证实鸭坦布苏病毒(FX2010)可以通过气溶胶途径在鸭群中迅速传播，而与FX2010亲缘关系接近的蚊源坦布苏病毒（MM1775）却不能，进一步研究发现坦布苏病毒的E基因对于病毒获得空气传播能力至关重要。基于此，本研究拟通过反向遗传操作技术，把FX2010与MM1775的E蛋白差异结构域基因进行相互替换或定点突变，构建携带不同结构域的嵌合病毒和点突变病毒，通过在鸭之间传播实验确定坦布苏病毒获得空气传播能力关键的E蛋白功能区域和氨基酸位点，并检测这些氨基酸位点改变对坦布苏病毒增殖能力和受体结合能力的影响，深入解析鸭坦布苏病毒获得空气传播能力的分子机制。

2010年以来，我国新发的坦布苏病毒（Tembusu virus, TMUV）的爆发和快速传播给养鸭业造成了巨大的经济损失。作为黄病毒属的成员，该病毒的传播机制等重大的科学问题还属于空白阶段。为研究上述科学问题，本研究通过反向遗传操作技术，将鸭坦布苏病毒FX2010与蚊源坦布苏病毒MM1775的E蛋白不同的结构域和差异氨基酸位点进行了相互替换或定点突变，构建携带不同结构域的嵌合病毒和点突变病毒，通过试验证明了坦布苏病毒的E蛋白及其结构域Ⅰ与病毒在鸭体内的组织嗜性和鸭间的传播密切相关。进一步研究证实E蛋白结构域Ⅰ上的S156P突变导致坦布苏病E蛋白N154糖基化的丧失，影响了E蛋白“150环”构像，从而改变了病毒在鸭体内的组织嗜性和在鸭间的传播能力，这些数据也显示了E蛋白156S对TMUV不依赖蚊媒而获得鸭间传播能力至关重要，研究首次发现了坦布苏病毒获得鸭间传播能力的关键氨基酸位点是E蛋白结构域Ⅰ的第156位氨基酸，该研究解析了坦布苏病毒获得传播能力相关的机制。