Since their discovery more than 100 years ago, the viruses that infect bacteria (bacteriophages) have been widely studied as model systems. Largely overlooked, however, have been “jumbo phages,” with genome sizes ranging from 200 to 500 kbp. Jumbo phages generally have large virions with complex structures and a broad host spectrum. While the majority of jumbo phage genes are poorly functionally characterized, recent work has discovered many unique biological features, including a conserved tubulin homolog that coordinates a proteinaceous nucleus-like compartment that houses and segregates phage DNA. The tubulin spindle displays dynamic instability and centers the phage nucleus within the bacterial host during phage infection for optimal reproduction. The shell provides robust physical protection for the enclosed phage genomes against attack from DNA-targeting bacterial immune systems, thereby endowing jumbo phages with broad resistance. In this review, we focus on the current knowledge of the cytoskeletal elements and the specialized nuclear compartment derived from jumbo phages, and we highlight their importance in facilitating spatial and temporal organization over the viral life cycle. Additionally, we discuss the evolutionary relationships between jumbo phages and eukaryotic viruses, as well as the therapeutic potential and drawbacks of jumbo phages as antimicrobial agents in phage therapy.

中文翻译：

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超大噬菌体的细胞内组织。

自从100多年前发现以来，感染细菌（噬菌体）的病毒已作为模型系统得到了广泛研究。然而，被忽视的是“巨型噬菌体”，其基因组大小在200至500 kbp之间。巨噬细胞通常具有结构复杂且宿主谱广的大型病毒体。尽管大多数巨型噬菌体基因在功能上均较差，但最近的工作发现了许多独特的生物学特征，包括保守的微管蛋白同源物，可协调容纳和分离噬菌体DNA的蛋白核样区室。微管蛋白纺锤体表现出动态不稳定性，并在噬菌体感染期间使细菌宿主内的噬菌体核居中，以实现最佳繁殖。壳为封闭的噬菌体基因组提供强大的物理保护，使其免受靶向DNA的细菌免疫系统的攻击，从而赋予巨型噬菌体以广泛的抵抗力。在这篇综述中，我们关注于目前从巨型噬菌体衍生的细胞骨架成分和特殊核区室的知识，并着重强调了它们在促进病毒生命周期中时空组织方面的重要性。此外，我们讨论了巨噬细胞和真核病毒之间的进化关系，以及巨噬细胞作为抗微生物剂在噬菌体治疗中的治疗潜力和缺点。我们关注于目前从巨噬细胞噬菌体衍生的细胞骨架成分和特殊核区室的知识，并且我们强调它们在促进病毒生命周期中的时空组织方面的重要性。此外，我们讨论了巨噬细胞和真核病毒之间的进化关系，以及巨噬细胞作为抗微生物剂在噬菌体治疗中的治疗潜力和缺点。我们关注于目前从巨噬细胞噬菌体衍生的细胞骨架成分和特殊核区室的知识，并且我们强调它们在促进病毒生命周期中的时空组织方面的重要性。此外，我们讨论了巨噬细胞和真核病毒之间的进化关系，以及巨噬细胞作为抗微生物剂在噬菌体治疗中的治疗潜力和缺点。