Borrelia (Borreliella) burgdorferi, along with closely related species, is the etiologic agent of Lyme disease. The spirochete subsists in an enzootic cycle that encompasses acquisition from a vertebrate host to a tick vector and transmission from a tick vector to a vertebrate host. To adapt to its environment and persist in each phase of its enzootic cycle, B. burgdorferi wields three systems to regulate the expression of genes: the RpoN-RpoS alternative sigma (σ) factor cascade, the Hk1/Rrp1 two-component system and its product c-di-GMP, and the stringent response mediated by Rel_Bbu and DksA. These regulatory systems respond to enzootic phase-specific signals and are controlled or fine- tuned by transcription factors, including BosR and BadR, as well as small RNAs, including DsrABb and Bb6S RNA. In addition, several other DNA-binding and RNA-binding proteins have been identified, although their functions have not all been defined. Global changes in gene expression revealed by high-throughput transcriptomic studies have elucidated various regulons, albeit technical obstacles have mostly limited this experimental approach to cultivated spirochetes. Regardless, we know that the spirochete, which carries a relatively small genome, regulates the expression of a considerable number of genes required for the transitions between the tick vector and the vertebrate host as well as the adaptation to each.

中文翻译：

---

基因调控和转录组学。

伯氏疏螺旋体( Borreliella ) burgdorferi以及密切相关的物种是莱姆病的病原体。螺旋体存在于一个地方性循环中，该循环包括从脊椎动物宿主到蜱载体的获取以及从蜱载体到脊椎动物宿主的传播。为了适应其环境并在其地方性周期的每个阶段持续存在，B. burgdorferi使用三个系统来调节基因的表达：RpoN-RpoS 替代 sigma (σ) 因子级联、Hk1/Rrp1 双组分系统及其产品 c-di-GMP，以及 Rel _{Bbu介导的严格反应}和 DksA。这些调节系统对地方性动物阶段特异性信号作出反应，并由包括 BosR 和 BadR 在内的转录因子以及包括 DsrABb 和 Bb6S RNA 在内的小 RNA 控制或微调。此外，已经鉴定了其他几种 DNA 结合和 RNA 结合蛋白，尽管它们的功能尚未全部确定。高通量转录组研究揭示的基因表达的全球变化已经阐明了各种调节子，尽管技术障碍主要限制了这种用于培养螺旋体的实验方法。无论如何，我们知道螺旋体携带相对较小的基因组，它调节蜱载体和脊椎动物宿主之间的转换以及对每种基因的适应所需的大量基因的表达。