Expansion of enterococcal insertion sequence elements during bacteriophage infection

项目总结 耐多药肠球菌感染是一个严重的公共卫生威胁。肠球菌，包括 粪肠球菌通常对关键的一线药物如氨苄西林和/或万古霉素具有耐药性。 由于目前可用的药物治疗肠球菌感染的难度越来越大，替代方案 治疗方案是必要的。一种可能性是细菌病毒的治疗用途，称为 噬菌体(噬菌体)虽然噬菌体疗法在临床上显示出了希望，但噬菌体的出现 细菌中的耐药性是未来噬菌体疗法的一个严重问题。要克服这一点，我们需要 了解细菌如何在基因水平上对噬菌体感染做出反应，以及 噬菌体抗性。我们实验室过去的工作发现，粪肠球菌对裂解噬菌体19(Phi19)具有抗性。 感染在它们的基因组中含有更多的IS256转座元件插入。这些 通常在与噬菌体感染有关的基因中发现插入片段，这表明phi19感染 刺激IS256转座创造新的遗传组合，导致抗噬菌体抗体。我的 初步研究表明，phi19感染可激活IS256动员。我已经找到了phi19 感染增加了IS256转座酶的翻译，而phi19编码的转录因子 类似于一种名为PAS19的抗Sigma因子，可增加IS256转座酶的翻译。这表明， PAS19负责在phi19感染过程中激活IS256。这个项目的目标是破译 粪肠球菌基因组进化响应噬菌体驱动的IS256激活，以及这些下游是如何 这些效应可以为噬菌体的治疗策略提供参考。为了实现这些目标，我将执行两个具体目标：目标 1：为噬菌体诱导粪肠球菌中IS256插入片段的扩增奠定了机制基础。工作 以此为目的，将展示噬菌体介导的功能性酶的需求和时机 IS256激活，并将确定这一活动是否广泛适用于各种肠球菌噬菌体；目标2： 确定假定的噬菌体转录因子如何控制IS256的激活。PAS19，推定为 由phi19编码的转录因子激活IS256的表达。在这个目标中，我将描述PAS19如何 控制IS256基因激活。

PROJECT SUMMARY Multidrug resistant enterococcal infections are a serious public health threat. The enterococci, including Enterococcus faecalis, often harbor resistance to critical front-line drugs such as ampicillin and/or vancomycin. Due to the increasing difficulty of treating enterococcal infections with currently available drugs, alternative treatment options are needed. One possibility is the therapeutic use of bacterial viruses known as bacteriophages (phages). While phage therapy has shown promise in the clinic, the emergence of phage resistance in bacteria is a serious concern for future phage therapies. To overcome this, we need to understand how bacteria respond to phage infection at the genetic level and the physiological consequences of phage resistance. Past work in our lab discovered that E. faecalis isolates resistant to lytic phage 19 (phi19) infection harbored an increased number of IS256 transposable element insertions in their genomes. These insertions were commonly found in genes involved in phage infection, suggesting that phi19 infection stimulates IS256 transposition to create new genetic combinations, leading to phage resistance. My preliminary work has demonstrated that phi19 infection activates IS256 mobilization. I have found that phi19 infection increases the translation of the IS256 transposase, and that a phi19-encoded transcription factor that resembles an anti-sigma factor, termed PAS19, increases IS256 transposase translation. This indicates that PAS19 is responsible for activating IS256 during phi19 infection. The goals of this project are to decipher how the E. faecalis genome evolves in response to phage driven IS256 activation, and how these downstream effects can inform phage therapeutic strategies. To achieve these goals, I will execute two specific aims: Aim 1: Establish a mechanistic basis for phage-induced expansion of IS256 insertions in E. faecalis. Work performed in this aim will demonstrate the functional enzymatic requirements and timing of phage mediated IS256 activation, and will determine if this activity is broadly applicable to diverse enterococcal phages; Aim 2: Determine how a putative phage transcription factor controls IS256 activation. PAS19, a putative transcription factor encoded by phi19 activates IS256 expression. In this aim, I will delineate how PAS19 controls IS256 gene activation.