Genome organization in double-stranded DNA viruses observed by cryoET.
Genome organization in double-stranded DNA viruses observed by cryoET.
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通过 CryoET 观察双链 DNA 病毒的基因组组织。
DOI：
10.1101/2023.12.15.571939
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发表时间：
2023
期刊：
影响因子：
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通讯作者：
Dai,Xinghong
中科院分区：
文献类型：
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作者：
Chen,Muyuan;Sahoo,Bibekananda;Mou,Zongjun;Song,Xiyong;Tsai,Tiffany;Dai,Xinghong
双链DNA（dsDNA）病毒将其遗传物质包装成直径通常比其基因组长度小几百倍的蛋白质笼。将相对刚性和高度带负电荷的dsDNA压缩成小体积在能量上是昂贵的并且在机械上是谜。基于各种实验证据和模拟方法，已经提出了多种dsDNA包装模型，但缺乏对任何病毒基因组组织的直接观察。在这里，使用cryoET和一个改进的数据处理方案，利用信息的包裹蛋白质壳，我们提出了三维视图的dsDNA基因组内的单个病毒颗粒的分辨率，相邻的DNA双链体的密度是很容易分离的。这些cryoET观察揭示了dsDNA的“棒-螺旋”折叠，其在具有球形衣壳的1型单纯疱疹病毒（HSV-1）、具有扁长衣壳的噬菌体T4和具有衣壳内的蛋白质核心的噬菌体T7中是保守的。最后，受部分包装的T4颗粒中的基因组排列的启发，我们提出了dsDNA病毒中基因组包装过程的机制。
Double-stranded DNA (dsDNA) viruses package their genetic material into protein cages with diameters usually a few hundred times smaller than the length of their genome. Compressing the relatively stiff and highly negatively charged dsDNA into a small volume is energetically costly and mechanistically enigmatic. Multiple models of dsDNA packaging have been proposed based on various experimental evidence and simulation methods, but direct observation of any viral genome organization is lacking. Here, using cryoET and an improved data processing scheme that utilizes information from the encaging protein shell, we present 3D views of dsDNA genome inside individual viral particles at resolution that densities of neighboring DNA duplexes are readily separable. These cryoET observations reveal a “rod-and-coil” fold of the dsDNA that is conserved among herpes simplex virus type 1 (HSV-1) with a spherical capsid, bacteriophage T4 with a prolate capsid, and bacteriophage T7 with a proteinaceous core inside the capsid. Finally, inspired by the genome arrangement in partially packaged T4 particles, we propose a mechanism for the genome packaging process in dsDNA viruses.