囊膜蛋白K326E突变导致坦布苏病毒毒力致弱的机制

坦布苏病毒属于黄病毒科黄病毒属，是当前严重危害水禽的传染病病原，该病毒对哺乳动物和人类还具有潜在危害。经脑内接种低剂量的坦布苏病毒FX2010-2株可以100%致死小鼠，而E蛋白发生K326E突变后，感染剂量提高100倍仍然不能杀死小鼠；感染小鼠后，EK326E突变株反而可以抑制α干扰素表达，这一现象在黄病毒属病毒中未见报道。本研究拟利用坦布苏病毒FX2010-2株和EK326E突变株的生物学特性差异，研究E蛋白326位氨基酸差异导致病毒感染过程中诱导或抑制α干扰素表达的机制；通过酵母双杂交、液相色谱-质谱联用分析、免疫共沉淀、shRNA阻断等方法，寻找与E蛋白突变体互作的差异蛋白，阐明EK326E突变抑制I型干扰素表达的机制，进而阐明I型干扰素表达被抑制时，宿主降低坦布苏病毒病理损伤的机制。该研究以单点突变病毒为背景，精确挖掘坦布苏病毒致病机制，为黄病毒属病毒致病机制研究提供新思路。

Tembusu virus belonging to the flavivirus genus of the flaviridae family, is the causative agent of a severe infectious disease in waterfowl and has potential harm to some mammals and human beings. It was found that low doses of Tembusu virus FX2010-2 could kill 100% of mice inoculated intracerebrally. But the EK326E mutant could not kill any mice inoculated intracerebrally at the dose increased even by 100 times. When the two strains infected mice respectively, the attenuated strain EK326E mutant could inhibit the expression of alpha interferon instead, which was not reported in other flaviviruses. In this study, Tembusu virus FX2010-2 strain and EK326E mutant were used to explore the mechanism of inducing or inhibiting alpha interferon expression in the process of infection, which was caused by differences of the amino acids at the position 326 of E protein. The different proteins interact with different E mutants will be found through Yeast-two hybrid technique, liquid chromatography and mass spectrometry analysis, immune co-precipitation, shRNA blocking methods and so on. The mechanism of inhibition of the expression of type I interferon by EK326E mutation will be clarified in this study, thus illustrating the mechanism that host inhibits Tembusu virus, even if the type I interferon expression are suppressed. Based on the background of single amino acid mutant virus, this study excavated precisely the pathogenic mechanism of Tembusu virus, which will provide a new idea for the studies of the pathogenic mechanism of other flaviviruses.