Comparative genomics analysis of three conserved plasmid families in the Western Hemisphere soft tick-borne relapsing fever borreliae provides insight into variation in genome structure and antigenic variation systems.
Comparative genomics analysis of three conserved plasmid families in the Western Hemisphere soft tick-borne relapsing fever borreliae provides insight into variation in genome structure and antigenic variation systems.
复制标题
对西半球软蜱传播回归热疏螺旋体中三个保守质粒家族的比较基因组学分析提供了对基因组结构和抗原变异系统变异的深入了解。
DOI：
10.1101/2023.03.06.531354
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Lopez,JobE
中科院分区：
文献类型：
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作者：
Kneubehl,AlexanderR;Lopez,JobE
螺旋体螺旋体是莱姆病和复发性发热(RF)的病原体，具有独特的复杂基因组，由线性染色体和环状和线状两种质粒组成。这些质粒含有对这些壁虱传播细菌的媒介-宿主生命周期至关重要的基因。与RFB相比，来自莱姆病的质粒引起螺旋体的作用更精细，这是因为后者的有限的由质粒解析的基因组组装。我们最近解决了这一限制，并发现三个线性质粒家族(F6、F27和F28)在我们检查的所有RF型疏螺旋体中都是同线的。鉴于这一保守性，我们进一步研究了这三个质粒家族。F6家族，也被称为巨质粒，包含重复的DNA区域。F27是最小的，编码未知功能的基因。F28家族编码除海南疏螺旋体和鹅疏螺旋体外的所有物种的抗原变异的可能的表达位点。综上所述，这项工作为未来的研究提供了基础，以确定驱动RFBorrelia.ImPORTANCEBorreliaspp载体-宿主生命周期的重要的质粒定位基因。螺旋体是一种由节肢动物传播的细菌，在全球范围内都能感染人类和其他脊椎动物。RF疏螺旋体是一种未被充分研究和误诊的病原体，这是由于其临床表现不明确，以及难以捉摸的吸食行为所致。因此，RF螺旋体的基因组学资源一直是有限的。对疏螺旋体质粒的分析一直具有挑战性，因为它们在大多数可用基因组组合中往往高度碎片化和解体。通过利用牛津纳米孔技术，我们最近为7个疏螺旋体产生了质粒解析的基因组组装。产于西半球。目前的研究是对跨物种保守和同线的线形质粒的深入研究。我们确定了不同物种之间基因组结构的差异，更重要的是，在抗原变异系统方面的差异。这项工作是鉴定关键的质粒定位遗传元件的重要一步，这些遗传元件对RF螺旋体的生命周期至关重要。
Borreliaspirochetes, causative agents of Lyme disease and relapsing fever (RF), have uniquely complex genomes, consisting of a linear chromosome and both circular and linear plasmids. The plasmids harbor genes important for the vector-host life cycle of these tick-borne bacteria. The role of plasmids from Lyme disease causing spirochetes is more refined compared to RFBorreliabecause of limited plasmid-resolved genome assemblies for the latter. We recently addressed this limitation and found that three linear plasmid families (F6, F27, and F28) were syntenic across all the RFBorreliaspecies that we examined. Given this conservation, we further investigated the three plasmid families. The F6 family, also known as the megaplasmid, contained regions of repetitive DNA. The F27 was the smallest, encoding genes with unknown function. The F28 family encoded the putative expression locus for antigenic variation in all species exceptBorrelia hermsiiandBorrelia anserina. Taken together, this work provides a foundation for future investigations to identify essential plasmid-localized genes that drive the vector-host life cycle of RFBorrelia.IMPORTANCEBorreliaspp. spirochetes are arthropod-borne bacteria found globally that infect humans and other vertebrates. RF borreliae are understudied and misdiagnosed pathogens because of the vague clinical presentation of disease and the elusive feeding behavior of argasid ticks. Consequently, genomics resources for RF spirochetes have been limited. Analyses ofBorreliaplasmids have been challenging because they are often highly fragmented and unassembled in most available genome assemblies. By utilizing Oxford Nanopore Technologies, we recently generated plasmid-resolved genome assemblies for sevenBorreliaspp. found in the Western Hemisphere. This current study is an in-depth investigation into the linear plasmids that were conserved and syntenic across species. We identified differences in genome structure and, importantly, in antigenic variation systems between species. This work is an important step in identifying crucial plasmid-localized genetic elements essential for the life cycle of RF spirochetes.