Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA.
Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
Sci Adv. 2022 May 6;8(18):eabj9670. doi: 10.1126/sciadv.abj9670. Epub 2022 May 4.
Many eukaryotic viruses assemble mature particles within distinct subcellular compartments, but bacteriophages are generally assumed to assemble randomly throughout the host cell cytoplasm. Here, we show that viral particles of nucleus-forming jumbo phage PhiPA3 assemble into a unique structure inside cells we term phage bouquets. We show that after capsids complete DNA packaging at the surface of the phage nucleus, tails assemble and attach to capsids, and these particles accumulate over time in a spherical pattern, with tails oriented inward and the heads outward to form bouquets at specific subcellular locations. Bouquets localize at the same fixed distance from the phage nucleus even when it is mispositioned, suggesting an active mechanism for positioning. These results mark the discovery of a pathway for organizing mature viral particles inside bacteria and demonstrate that nucleus-forming jumbo phages, like most eukaryotic viruses, are highly spatially organized during all stages of their lytic cycle.
许多真核病毒在特定的亚细胞隔室中组装成熟的颗粒，但噬菌体通常被认为是在宿主细胞质中随机组装的。在这里，我们展示了形成核的巨型噬菌体 PhiPA3 的病毒颗粒在我们称之为噬菌体花束的细胞内组装成一种独特的结构。我们表明，在衣壳完成了在噬菌体核表面的 DNA 包装之后，尾部组装并附着到衣壳上，并且这些颗粒随着时间的推移以球形模式积累，尾部向内，头部向外，在特定的亚细胞位置形成花束。即使噬菌体核错位，花束也会固定在距噬菌体核相同的位置，这表明存在一种用于定位的主动机制。这些结果标志着在细菌内部组织成熟病毒颗粒的途径的发现，并表明形成核的巨型噬菌体与大多数真核病毒一样，在其裂解周期的所有阶段都具有高度的空间组织性。
