Alteromonas Myovirus V22 Represents a New Genus of Marine Bacteriophages Requiring a Tail Fiber Chaperone for Host Recognition
Alteromonas Myovirus V22 Represents a New Genus of Marine Bacteriophages Requiring a Tail Fiber Chaperone for Host Recognition
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DOI：
10.1128/msystems.00217-20
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发表时间：
2020-05-01
期刊：
影响因子：
6.4
通讯作者：
Rodriguez-Valera, Francisco
中科院分区：
文献类型：
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作者：
Gonzalez-Serrano, Rafael;Dunne, Matthew;Rodriguez-Valera, Francisco
海洋噬菌体在调节海洋微生物组成方面发挥着各种关键作用。尽管构成了这些环境中的大部分遗传多样性，但相对较少的分离物具有完整的基因组序列或对其宿主相互作用机制进行深入分析，例如对其受体结合蛋白（rbp）的表征。在这里，我们展示了针对alteromonas的噬菌体V22的92,760 bp的基因组。基因组和形态学分析鉴定V22为肌病毒；然而，由于与任何其他已知的肌病毒缺乏序列相似性，我们建议将V22归类为肌病毒科中一个新的肌alterovirus属的型噬菌体。V22与感染肠杆菌的噬菌体的两个不同亚科具有基因同源性，特别是在其基因组的结构区域内。为了进一步了解V22的吸附过程，我们鉴定了推测的rbp (gp23、gp24和gp26)，并测试了它们作为重组绿色荧光蛋白（GFP）标记的构建物修饰V22繁殖菌株地中海Alteromonas mediterranea PT11的能力。只有GFP-gp26具有细菌识别能力，被鉴定为V22 RBP。有趣的是，功能性GFP-gp26的产生需要与下游蛋白gp27共表达。GFP-gp26可以单独表达，但不能识别宿主。通过结合大小排斥色谱法和荧光显微镜，我们揭示了gp27不是最终RBP复合物的组成部分，而是被鉴定为一种新型的噬菌体编码分子间伴侣，对gp26 RBP的成熟至关重要。噬菌体编码受体结合蛋白（rbp）对宿主的识别是所有噬菌体感染的第一步，也是决定宿主特异性的最关键因素。通过表征新型rbp和鉴定其基本伴侣，我们希望扩大已知噬菌体-宿主识别机制的曲目。由于它们的遗传可塑性，研究rbp及其相关的伴侣蛋白可以为研究影响噬菌体-宿主相互作用的病毒进化提供新的线索，这对噬菌体治疗或生物技术等领域至关重要。此外，由于海洋噬菌体是地球上最重要的非特征遗传多样性储存库之一，它们的基因组和功能特征可能对发现具有潜在应用价值的新基因至关重要。
Marine phages play a variety of critical roles in regulating the microbial composition of our oceans. Despite constituting the majority of genetic diversity within these environments, there are relatively few isolates with complete genome sequences or in-depth analyses of their host interaction mechanisms, such as characterization of their receptor binding proteins (RBPs). Here, we present the 92,760-bp genome of the Alteromonas-targeting phage V22. Genomic and morphological analyses identify V22 as a myovirus; however, due to a lack of sequence similarity to any other known myoviruses, we propose that V22 be classified as the type phage of a new Myoalterovirus genus within the Myoviridae family. V22 shows gene homology and synteny with two different subfamilies of phages infecting enterobacteria, specifically within the structural region of its genome. To improve our understanding of the V22 adsorption process, we identified putative RBPs (gp23, gp24, and gp26) and tested their ability to decorate the V22 propagation strain, Alteromonas mediterranea PT11, as recombinant green fluorescent protein (GFP)-tagged constructs. Only GFP-gp26 was capable of bacterial recognition and identified as the V22 RBP. Interestingly, production of functional GFP-gp26 required coexpression with the downstream protein gp27. GFP-gp26 could be expressed alone but was incapable of host recognition. By combining size-exclusion chromatography with fluorescence microscopy, we reveal how gp27 is not a component of the final RBP complex but instead is identified as a new type of phage-encoded intermolecular chaperone that is essential for maturation of the gp26 RBP.IMPORTANCE Host recognition by phage-encoded receptor binding proteins (RBPs) constitutes the first step in all phage infections and the most critical determinant of host specificity. By characterizing new types of RBPs and identifying their essential chaperones, we hope to expand the repertoire of known phage-host recognition machineries. Due to their genetic plasticity, studying RBPs and their associated chaperones can shed new light onto viral evolution affecting phage-host interactions, which is essential for fields such as phage therapy or biotechnology. In addition, since marine phages constitute one of the most important reservoirs of noncharacterized genetic diversity on the planet, their genomic and functional characterization may be of paramount importance for the discovery of novel genes with potential applications.