Visualizing virus assembly intermediates inside marine cyanobacteria.
Visualizing virus assembly intermediates inside marine cyanobacteria.
复制标题
作者：
蓝细菌是光合生物，负责地球上约25%的有机碳固定。这些细菌在数十亿年前就开始将太阳能和二氧化碳转化为生物能和氧气。噬藻体感染这些细菌，通过控制蓝藻群落组织和介导横向基因转移在调节海洋生态系统中发挥重要作用。在这里，我们可视化的成熟过程中的噬藻体Syn5在其宿主细胞，聚球藻，使用泽尔尼克相位对比（ZPC）电子冷冻断层扫描（cryoET）。这种成像方式产生显着增强的图像对比度超过传统的冷冻ET，从而有利于直接识别的亚细胞成分，包括类囊体膜，羧基体和多聚核糖体，以及在受感染的细胞的拥挤的胞质溶胶内。通过将感染不同阶段的细胞内病毒子代的结构特征和相对丰度相关联，我们鉴定了不同的Syn5组装中间体。我们的研究结果表明，在基因组包装的早期阶段，原衣壳释放支架蛋白并扩大其体积。在后来的组装中，我们检测到了带有尾巴的完整粒子，无论是否有额外的角。我们在此描述的形态发生途径是高度保守的，并且可能在双链DNA（dsDNA）病毒感染高等生命形式之前很久就建立了。
Cyanobacteria are photosynthetic organisms responsible for ~25% of organic carbon fixation on earth. These bacteria began to convert solar energy and carbon dioxide into bioenergy and oxygen billions of years ago. Cyanophages, which infect these bacteria, play an important role in regulating the marine ecosystem by controlling cyanobacteria community organization and mediating lateral gene transfer. Here we visualize the maturation process of cyanophage Syn5 inside its host cell, Synechococcus, using Zernike Phase Contrast (ZPC) electron cryo-tomography (cryoET). This imaging modality yields significant enhancement of image contrast over conventional cryoET and thus facilitates the direct identification of subcellular components, including thylakoid membranes, carboxysomes and polyribosomes, as well as phages, inside the congested cytosol of the infected cell. By correlating the structural features and relative abundance of viral progeny within cells at different stages of infection, we identified distinct Syn5 assembly intermediates. Our results suggest that the procapsid releases scaffolding proteins and expands its volume at an early stage of genome packaging. Later in assembly, we detected full particles with a tail either with or without an additional horn. The morphogenetic pathway we describe herein is highly conserved and was probably established long before that of double stranded DNA (dsDNA) viruses infecting higher life forms.
登录
查看更多内容
DOI：
10.1126/science.1231887
发表时间：
2013-02-01
期刊：
Science (New York, N.Y.)
影响因子：
--
作者：
Hu B;Margolin W;Molineux IJ;Liu J
通讯作者：
Liu J
影响因子：
5.7
作者：
Murata, Kazuyoshi;Liu, Xiangan;Chiu, Wah
通讯作者：
Chiu, Wah
影响因子：
4.4
作者：
Fuller, NJ;Marie, D;Scanlan, DJ
通讯作者：
Scanlan, DJ
影响因子：
3
作者：
Schmid, Michael F.;Booth, Christopher R.
通讯作者：
Booth, Christopher R.
影响因子：
3
作者：
Kremer, JR;Mastronarde, DN;McIntosh, JR
通讯作者：
McIntosh, JR