A small RNA regulation of virulence in Lyme disease pathogen

项目总结/摘要 莱姆病是一种普遍的节肢动物传播疾病，由细菌病原体伯氏疏螺旋体引起。 微生物生活在一个复杂的地方性生活周期中，涉及硬蜱、蜱和各种哺乳动物物种。 在复杂的循环中生存并在不同的组织环境中导航，例如在 哺乳动物宿主或蜱中，B. burgdorferi必须在一个紧密的时间和空间上调节基因表达， 尽管这种基因调控的机制尚不清楚。转录后基因 通过各种小的调节RNA（sRNA）的调节是调节基因表达的一种机制， 细菌sRNA和靶mRNA之间的碱基配对可以触发mRNA翻译的改变， 稳定性，从而影响靶基因表达。小RNA也与蛋白质结合， 或影响蛋白质的活性。先前的研究报道了一种小RNA DsrABb调节RpoS B中的基因表达。burgdorferi。此外，最近的研究确定了超过1000个B。Burgdorferi sRNAs， 差异调节的环境条件，这表明sRNAs可能在基因调控中发挥作用， 在其地方性流行周期中，尽管它们在螺旋体中的精确功能或重要性， 生物学和传染性在很大程度上仍然是个谜。最近，一个基因间非编码小RNA位于 bbd 18的上游，称为ittA，被表征并显示为最佳感染性和组织所需 B中的向性。burgdorferi。事实上，据报道bbd 17和bbd 18的基因间区域含有一个小的 RNA 0735（SR 0735），其在37°C（哺乳动物宿主体温）下高度表达。我们的初步 数据显示在SR 0735上游插入卡那霉素盒影响B。伯氏菌感染性 北方印迹和RT-PCR分析显示，SR 0735的表达水平降低，提示了一个关键的 SR 0735在微生物毒力中的重要性。我们目前提案的目标是研究 研究这种sRNA在螺旋体生物学和毒力中的作用，并鉴定其潜在的靶RNA和/或蛋白结合 伙伴这项研究将揭示螺旋体生物学中的sRNA调控机制，并可能有助于 sRNA在螺旋体毒力和致病机制中的作用。

Project Summary/Abstract Lyme disease, a prevalent arthropod-borne disease, is caused by the bacterial pathogen Borrelia burgdorferi. The microbes live in an intricate enzootic life cycle involving both Ixodes ticks and diverse mammalian species. To survive in its complex cycle and navigate through disparate sets of tissue environments, such as ones in mammalian hosts or in ticks, B. burgdorferi must regulate gene expression in a tight temporal and spatial manner, although the mechanism of such gene regulation remains unclear. Posttranscriptional gene regulation via a variety of small regulatory RNAs (sRNAs) is one mechanism of modulating gene expression in bacteria. Base pairing between the sRNAs and target mRNAs can trigger alterations in mRNA translation and stability, thereby influencing target gene expression. The small RNAs also bind to proteins, either sequestering or affecting the activities of proteins. Previous studies have reported that a small RNA, DsrABb, regulates RpoS gene expression in B. burgdorferi. Moreover, recent studies identified over 1000 B. burgdorferi sRNAs that are differentially regulated by environmental conditions, suggesting that sRNAs may play a role in gene regulation for spirochete adaptation during its enzootic cycle, although their precise functions or importance in spirochete biology and infectivity remain largely enigmatic. Most recently, an intergenic non-coding small RNA located upstream of bbd18, called ittA, was characterized and shown to be required for optimal infectivity and tissue tropism in B. burgdorferi. In fact, the intergenic region of bbd17 and bbd18 was reported to harbor a small RNA 0735 (SR0735), that is highly expressed at 37°C (mammalian host body temperature). Our preliminary data showed that the insertion of a kanamycin cassette upstream of SR0735 affects B. burgdorferi infectivity and decreases the level of SR0735, as shown in Northern blot and RT-PCR analyses, suggesting a critical importance of SR0735 in microbial virulence. The goals of our current proposal are to study the potential role of this sRNA in spirochete biology and virulence, and to identify its potential target RNA and/or protein binding partners. This study will uncover the sRNA regulatory mechanisms in spirochete biology and may help to decipher the functions of sRNAs in spirochete virulence and pathogenesis.