Structural Studies Reveal that Endosomal Cations Promote Formation of Infectious Coxsackievirus A9 A-Particles, Facilitating RNA and VP4 Release.
Structural Studies Reveal that Endosomal Cations Promote Formation of Infectious Coxsackievirus A9 A-Particles, Facilitating RNA and VP4 Release.
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DOI：
10.1128/jvi.01367-22
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发表时间：
2022-12-21
影响因子：
5.4
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中科院分区：
文献类型：
--
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柯萨奇病毒A9（CVA 9）是一种肠道病毒，是儿科无菌性脑膜炎和新生儿败血症的常见原因。在进入细胞期间，肠道病毒衣壳经历构象变化，导致膨胀、大孔形成、VP 1 N末端外化和VP 1中脂质因子的丢失。受体结合、热和酸性pH等因素可触发某些肠道病毒的衣壳扩张。在这里，我们表明，不含脂肪酸的牛血清白蛋白或中性内体离子条件下可以独立地启动CVA 9的扩增和基因组释放。我们的研究结果表明，CVA 9治疗与白蛋白或内体离子产生的病毒粒子的异质群体，这可以物理分离的不对称流场流分级和计算冷冻电子显微镜（cryo-EM）和图像处理。我们报告的CVA 9 A-颗粒通过白蛋白或内体离子处理和对照非扩展病毒粒子的冷冻电镜结构，分别为3.5，3.3和2.9 μ m的分辨率。白蛋白促进稳定的扩增病毒体，而内体离子浓度诱导不稳定的CVA 9病毒体，其容易解体，丢失其基因组。大部分VP 4分子的丢失和衣壳内部带负电荷的氨基酸残基在扩增后的暴露产生了排斥性的病毒RNA-衣壳界面，有助于基因组释放。柯萨奇病毒A9（CVA 9）是脑膜炎和新生儿败血症的常见原因。RNA释放到细胞中的触发器和作用模式不需要受体相互作用。相反，需要内体中的缓慢过程，不依赖于低pH。在这里，我们通过生物物理分离，低温电子显微镜，和图像重建，白蛋白和缓冲液模仿内体离子组合物可以单独和一起扩大和总理CVA 9脱壳。此外，我们在这些扩展的颗粒中显示，VP 4仅以病毒体中发现的占用率的约10%存在，VP 1被外部化，并且基因组被由于扩展而发生的衣壳的带负电荷的排斥性内表面排斥。因此，我们现在可以将感染的细胞生物学观察与衣壳中发生的物理过程联系起来，以促进基因组的脱壳。
Coxsackievirus A9 (CVA9), an enterovirus, is a common cause of pediatric aseptic meningitis and neonatal sepsis. During cell entry, enterovirus capsids undergo conformational changes leading to expansion, formation of large pores, externalization of VP1 N termini, and loss of the lipid factor from VP1. Factors such as receptor binding, heat, and acidic pH can trigger capsid expansion in some enteroviruses. Here, we show that fatty acid-free bovine serum albumin or neutral endosomal ionic conditions can independently prime CVA9 for expansion and genome release. Our results showed that CVA9 treatment with albumin or endosomal ions generated a heterogeneous population of virions, which could be physically separated by asymmetric flow field flow fractionation and computationally by cryo-electron microscopy (cryo-EM) and image processing. We report cryo-EM structures of CVA9 A-particles obtained by albumin or endosomal ion treatment and a control nonexpanded virion to 3.5, 3.3, and 2.9 Å resolution, respectively. Whereas albumin promoted stable expanded virions, the endosomal ionic concentrations induced unstable CVA9 virions which easily disintegrated, losing their genome. Loss of most of the VP4 molecules and exposure of negatively charged amino acid residues in the capsid’s interior after expansion created a repulsive viral RNA-capsid interface, aiding genome release. IMPORTANCE Coxsackievirus A9 (CVA9) is a common cause of meningitis and neonatal sepsis. The triggers and mode of action of RNA release into the cell unusually do not require receptor interaction. Rather, a slow process in the endosome, independent of low pH, is required. Here, we show by biophysical separation, cryogenic electron microscopy, and image reconstruction that albumin and buffers mimicking the endosomal ion composition can separately and together expand and prime CVA9 for uncoating. Furthermore, we show in these expanded particles that VP4 is present at only ~10% of the occupancy found in the virion, VP1 is externalized, and the genome is repelled by the negatively charged, repulsive inner surface of the capsid that occurs due to the expansion. Thus, we can now link observations from cell biology of infection with the physical processes that occur in the capsid to promote genome uncoating.
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影响因子：
3.4
作者：
Aldriweesh MA;Shafaay EA;Alwatban SM;Alkethami OM;Aljuraisi FN;Bosaeed M;Alharbi NK
通讯作者：
Alharbi NK
影响因子：
9.8
作者：
Brandenburg B;Lee LY;Lakadamyali M;Rust MJ;Zhuang X;Hogle JM
通讯作者：
Hogle JM
影响因子：
3
作者：
de la Rosa-Trevin, J. M.;Quintana, A.;Carazo, J. M.
通讯作者：
Carazo, J. M.
影响因子：
9.2
作者：
Gerasimenko, JV;Tepikin, AV;Gerasimenko, OV
通讯作者：
Gerasimenko, OV
影响因子：
5.4
作者：
Bilek, Gerhard;Matscheko, Nena M.;Blaas, Dieter
通讯作者：
Blaas, Dieter