BB0844, an RpoS-Regulated Protein, Is Dispensable for Borrelia burgdorferi Infectivity and Maintenance in the Mouse-Tick Infectious Cycle
BB0844, an RpoS-Regulated Protein, Is Dispensable for Borrelia burgdorferi Infectivity and Maintenance in the Mouse-Tick Infectious Cycle
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DOI：
10.1128/iai.01156-10
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发表时间：
2011-03-01
影响因子：
3.1
通讯作者：
Schwartz, Ira
中科院分区：
文献类型：
--
作者：
Banik, Sukalyani;Terekhova, Darya;Schwartz, Ira
莱姆病的病原体伯氏疏螺旋体的基因组由一个大的线性染色体和许多较小的线性和环状质粒组成。B。burgdorferi表现出实质性的基因组变异，并且先前的研究揭示了在右侧染色体端粒处的基因型特异性变异。基因型和侵袭性之间也建立了相关性。染色体长度和基因型之间的相关性，基因型和侵袭性之间的关系表明，在正确的染色体端粒的基因可能是需要的毒力。特别令人感兴趣的是bb 0844，一个Rpos调控的基因在正确的端粒，其表达诱导时，螺旋体经历适应哺乳动物宿主。在53 B中检查了右侧染色体端粒的结构。不同基因型的伯氏临床分离株。观察到bb 0844的四种不同模式：（i）染色体定位，（ii）质粒定位，（iii）在染色体和质粒上均存在，以及（iv）完全不存在。这些模式与B相关。burgdorferi基因型。在现有序列数据的基础上，我们提出了一种基因组重排的机制，占bb 0844基因组定位的变异性。为了进一步探索BB 0844在螺旋体生命周期中的作用，通过等位基因交换构建了bb 0844缺失突变体，并在实验小鼠-蜱感染模型中检查了野生型和bb 0844缺失突变体的活力。bb 0844突变体在C3 H/HeJ小鼠中通过针接种或用B蜱传播具有完全感染性。感染伯氏硬蜱的肩胛硬蜱幼虫。幼稚蜱幼虫从B获得野生型和突变型螺旋体的效率相同。感染伯氏菌的小鼠。结果表明，BB 0844不是蜱载体或哺乳动物宿主中螺旋体活力、致病性或维持所需的。目前，BB 0844在B. burgdorferi无法确定。
The genome of Borrelia burgdorferi, the causative agent of Lyme disease, is comprised of a large linear chromosome and numerous smaller linear and circular plasmids. B. burgdorferi exhibits substantial genomic variation, and previous studies revealed genotype-specific variation at the right chromosomal telomere. A correlation has also been established between genotype and invasiveness. The correlation between chromosome length and genotype and between genotype and invasiveness suggested that a gene(s) at the right chromosome telomere may be required for virulence. Of particular interest was bb0844, an RpoS-regulated gene at the right telomere, the expression of which is induced when the spirochete undergoes adaptation to the mammalian host. The structure of the right chromosomal telomere was examined in 53 B. burgdorferi clinical isolates of various genotypes. Four distinct patterns were observed for bb0844: (i) chromosomal localization, (ii) plasmid localization, (iii) presence on both chromosome and plasmid, and (iv) complete absence. These patterns correlated with the B. burgdorferi genotype. On the basis of available sequence data, we propose a mechanism for the genomic rearrangements that accounts for the variability in bb0844 genomic localization. To further explore the role of BB0844 in the spirochete life cycle, a bb0844 deletion mutant was constructed by allelic exchange, and the viability of wild-type and bb0844 deletion mutants was examined in an experimental mouse-tick infection model. The bb0844 mutant was fully infectious in C3H/HeJ mice by either needle inoculation or tick transmission with B. burgdorferi-infected Ixodes scapularis larvae. Naive larval ticks acquired both wild-type and mutant spirochetes with equal efficiency from B. burgdorferi-infected mice. The results demonstrate that BB0844 is not required for spirochete viability, pathogenicity, or maintenance in the tick vector or the mammalian host. At present, a defined role for BB0844 in B. burgdorferi cannot be ascertained.