Physico-chemical requirements and kinetics of membrane fusion of flavivirus-like particles.
Physico-chemical requirements and kinetics of membrane fusion of flavivirus-like particles.
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DOI：
10.1099/vir.0.000113
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发表时间：
2015-07
期刊：
影响因子：
--
通讯作者：
Modis Y
中科院分区：
文献类型：
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作者：
Espósito DL;Nguyen JB;DeWitt DC;Rhoades E;Modis Y
黄病毒通过将其脂质包膜与细胞膜融合，将其RNA基因组传递到宿主细胞质中。在缺乏其他病毒基因的情况下，黄病毒膜前和包膜糖蛋白基因的表达导致具有膜融合活性的病毒样颗粒（vlp）的自发组装和分泌。在这里，我们检测了西尼罗病毒和日本脑炎病毒VLPs膜融合的理化要求。在大量融合实验中，在37°C下观察到最佳的半融合（或脂质混合）效率。熔融效率随pH的降低而增加；pH 5.6达到半最大半灌注。当阴离子脂质（单酰基甘油）磷酸和磷脂酰肌醇-3-磷酸存在于靶膜中时，可显著提高融合效率，这与新兴的黄病毒与中晚期内体室融合的模型一致，这些内体室中脂质最丰富。在单颗粒融合实验中，在酸化后7-20秒的时间尺度上，VLPs催化膜半融合，以脂质与细胞膜混合的方式进行追踪。脂质混合动力学表明半灌注是一个动力学复杂的多步骤过程。
Flaviviruses deliver their RNA genome into the host-cell cytoplasm by fusing their lipid envelope with a cellular membrane. Expression of the flavivirus pre-membrane and envelope glycoprotein genes in the absence of other viral genes results in the spontaneous assembly and secretion of virus-like particles (VLPs) with membrane fusion activity. Here, we examined the physico-chemical requirements for membrane fusion of VLPs from West Nile and Japanese encephalitis viruses. In a bulk fusion assay, optimal hemifusion (or lipid mixing) efficiencies were observed at 37 °C. Fusion efficiency increased with decreasing pH; half-maximal hemifusion was attained at pH 5.6. The anionic lipids bis(monoacylglycero)phosphate and phosphatidylinositol-3-phosphate, when present in the target membrane, significantly enhanced fusion efficiency, consistent with the emerging model that flaviviruses fuse with intermediate-to-late endosomal compartments, where these lipids are most abundant. In a single-particle fusion assay, VLPs catalysed membrane hemifusion, tracked as lipid mixing with the cellular membrane, on a timescale of 7–20 s after acidification. Lipid mixing kinetics suggest that hemifusion is a kinetically complex, multistep process.