Plasmid Characteristics Modulate the Propensity of Gene Exchange in Bacterial Vesicles
Plasmid Characteristics Modulate the Propensity of Gene Exchange in Bacterial Vesicles
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DOI：
10.1128/jb.00430-18
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发表时间：
2019-04-01
影响因子：
3.2
通讯作者：
Boedicker, James Q.
中科院分区：
文献类型：
--
作者：
Tran, Frances;Boedicker, James Q.
水平基因转移负责多种遗传元素的交换，包括质粒。已知交换的遗传元件的性质会通过偶联、转导和转化的机制影响转移的效率。最近发现了另一种水平基因转移的一般途径，即通过细胞外囊泡进行基因交换。尽管细胞外囊泡已被证明可以促进几种质粒的交换，但质粒特性对囊泡内遗传交换的影响尚不清楚。本研究构建了一组不同的质粒，以系统地测试质粒特性，特别是质粒拷贝数、大小和复制起源对基因在囊泡中的转移的影响。每种性质对含有细菌质粒的囊泡的生产、包装和摄取的影响进行了量化，揭示了质粒性质如何调节囊泡介导的水平基因转移。质粒装载到囊泡中与质粒拷贝数相关，并受到有助于设置细胞内质粒数量的特征的影响，包括大小和复制的起源。质粒起源对囊泡装载和摄取也有单独的影响，这表明复制的起源是特定质粒在细胞外囊泡内转移倾向的主要决定因素。细胞外囊泡的形成和交换在细菌群中很常见。囊泡包装多种类型的生物分子，包括遗传物质。含有遗传物质的细胞外囊泡的交换促进了种间DNA的转移，可能是一种水平基因转移的混杂机制。与其他水平基因转移机制不同，目前尚不清楚交换DNA的特征是否会影响在囊泡中转移的可能性。在这里，我们系统地研究了质粒拷贝数、大小和复制起源对DNA装载到囊泡中的影响，以及受体细胞对含有DNA的囊泡的摄取。这些结果揭示了每种质粒特性如何影响基因在囊泡中的转移，并有助于更好地理解囊泡介导的基因交换在水平基因转移中的重要性。
Horizontal gene transfer is responsible for the exchange of many types of genetic elements, including plasmids. Properties of the exchanged genetic element are known to influence the efficiency of transfer via the mechanisms of conjugation, transduction, and transformation. Recently, an alternative general pathway of horizontal gene transfer has been identified, namely, gene exchange by extracellular vesicles. Although extracellular vesicles have been shown to facilitate the exchange of several types of plasmids, the influence of plasmid characteristics on genetic exchange within vesicles is unclear. Here, a set of different plasmids was constructed to systematically test the impact of plasmid properties, specifically, plasmid copy number, size, and origin of replication, on gene transfer in vesicles. The influence of each property on the production, packaging, and uptake of vesicles containing bacterial plasmids was quantified, revealing how plasmid properties modulate vesiclemediated horizontal gene transfer. The loading of plasmids into vesicles correlates with the plasmid copy number and is influenced by characteristics that help set the number of plasmids within a cell, including size and origin of replication. Plasmid origin also has a separate impact on both vesicle loading and uptake, demonstrating that the origin of replication is a major determinant of the propensity of specific plasmids to transfer within extracellular vesicles.IMPORTANCE Extracellular vesicle formation and exchange are common within bacterial populations. Vesicles package multiple types of biomolecules, including genetic material. The exchange of extracellular vesicles containing genetic material facilitates interspecies DNA transfer and may be a promiscuous mechanism of horizontal gene transfer. Unlike other mechanisms of horizontal gene transfer, it is unclear whether characteristics of the exchanged DNA impact the likelihood of transfer in vesicles. Here, we systematically examine the influence of plasmid copy number, size, and origin of replication on the loading of DNA into vesicles and the uptake of DNA containing vesicles by recipient cells. These results reveal how each plasmid characteristic impacts gene transfer in vesicles and contribute to a greater understanding of the importance of vesicle-mediated gene exchange in the landscape of horizontal gene transfer.