Gac Is a Transcriptional Repressor of the Lyme Disease Spirochete's OspC Virulence-Associated Surface Protein.
Gac Is a Transcriptional Repressor of the Lyme Disease Spirochete's OspC Virulence-Associated Surface Protein.
复制标题
DOI：
10.1128/jb.00440-22
复制
发表时间：
2023-04-25
影响因子：
3.2
通讯作者：
中科院分区：
文献类型：
--
作者：
OspC外表面脂蛋白是莱姆病螺旋体感染脊椎动物的初始阶段所必需的。未喂食扁虱的中肠内的细菌不表达SPC，但当扁虱开始摄取血液时，会产生高水平的细菌。莱姆病螺旋体在脊椎动物感染后1到2 周内停止产生OspC，而未能下调OspC的细菌会被宿主抗体清除。因此，对OspC水平的严格调控对莱姆疏螺旋体的生存至关重要，因此是开发新的治疗策略的一个有吸引力的目标。以往的研究确定，OspC启动子的DNA区域5‘，即OspC操纵子，是控制OspC产生所必需的。假设OspC操纵子可能结合了一个调节因子，进行了DNA亲和力下拉实验，并确定是由Gac蛋白结合的。GAC由GyrA开放阅读框的C末端结构域、内部启动子、核糖体结合位点和起始密码子编码。我们的分析表明，Gac对OspC操纵子和启动子DNA的亲和力比对其他测试的硼序列更大。体外和体内分析表明，Gac是OspC的转录抑制因子。这些结果为我们理解莱姆病螺旋体控制SPC产生的机制提供了实质性的进展。重要意义伯氏疏螺旋体需要其表面暴露的OspC蛋白才能在人类和其他脊椎动物宿主中建立感染。在传播过程中不产生OspC或在确定感染后未能抑制OspC的细菌会迅速被宿主清除。在此，我们鉴定了一种与OspC启动子和5‘端相邻DNA具有优先亲和力的丝状蛋白Gac。生化分析和对转基因细菌的研究相结合，证明Gac是OspC的转录抑制因子。这是在理解莱姆病螺旋体如何控制基本OSPC毒力因子的产生并确定预防和治疗的新靶点方面取得的实质性进展。
The OspC outer-surface lipoprotein is essential for the Lyme disease spirochete’s initial phase of vertebrate infection. Bacteria within the midguts of unfed ticks do not express OspC but produce high levels when ticks begin to ingest blood. Lyme disease spirochetes cease production of OspC within 1 to 2 weeks of vertebrate infection, and bacteria that fail to downregulate OspC are cleared by host antibodies. Thus, tight regulation of OspC levels is critical for survival of Lyme borreliae and, therefore, an attractive target for development of novel treatment strategies. Previous studies determined that a DNA region 5′ of the ospC promoter, the ospC operator, is required for control of OspC production. Hypothesizing that the ospC operator may bind a regulatory factor, DNA affinity pulldown was performed and identified binding by the Gac protein. Gac is encoded by the C-terminal domain of the gyrA open reading frame from an internal promoter, ribosome-binding site, and initiation codon. Our analyses determined that Gac exhibits a greater affinity for ospC operator and promoter DNAs than for other tested borrelial sequences. In vitro and in vivo analyses demonstrated that Gac is a transcriptional repressor of ospC. These results constitute a substantial advance to our understanding of the mechanisms by which the Lyme disease spirochete controls production of OspC. IMPORTANCE Borrelia burgdorferi sensu lato requires its surface-exposed OspC protein in order to establish infection in humans and other vertebrate hosts. Bacteria that either do not produce OspC during transmission or fail to repress OspC after infection is established are rapidly cleared by the host. Herein, we identified a borrelial protein, Gac, that exhibits preferential affinity to the ospC promoter and 5′ adjacent DNA. A combination of biochemical analyses and investigations of genetically manipulated bacteria demonstrated that Gac is a transcriptional repressor of ospC. This is a substantial advance toward understanding how the Lyme disease spirochete controls production of the essential OspC virulence factor and identifies a novel target for preventative and curative therapies.
登录
查看更多内容
影响因子：
3.1
作者：
Crother, TR;Champion, CI;Lovett, MA
通讯作者：
Lovett, MA
影响因子：
9.4
作者：
FINGERLE, V;HAUSER, U;WILSKE, B
通讯作者：
WILSKE, B
DOI：
10.1073/pnas.0401595101
发表时间：
2004-05-11
影响因子：
11.1
作者：
Corbett, KD;Shultzaberger, RK;Berger, JM
通讯作者：
Berger, JM
影响因子：
3.1
作者：
Antonara, Styliani;Ristow, Laura;Coburn, Jenifer
通讯作者：
Coburn, Jenifer
影响因子：
4.1
作者：
Fingerle, Volker;Goettner, Gereon;Schulte-Spechtel, Ulrike
通讯作者：
Schulte-Spechtel, Ulrike