Zhang Xue-Song, Blaser Martin J
Department of Medicine, New York University School of Medicine, New York, New York, USA.
J Bacteriol. 2012 Aug;194(15):3891-903. doi: 10.1128/JB.00346-12. Epub 2012 May 18.
For naturally competent microorganisms, such as Helicobacter pylori, the steps that permit recombination of exogenous DNA are not fully understood. Immediately downstream of an H. pylori gene (dprA) that facilitates high-frequency natural transformation is HP0334 (dprB), annotated to be a putative Holliday junction resolvase (HJR). We showed that the HP0334 (dprB) gene product facilitates high-frequency natural transformation. We determined the physiologic roles of DprB by genetic analyses. DprB controls in vitro growth, survival after exposure to UV or fluoroquinolones, and intragenomic recombination. dprB ruvC double deletion dramatically decreases both homologous and homeologous transformation and survival after exposure to DNA-damaging agents. Moreover, the DprB protein binds to synthetic Holliday junction structures rather than double-stranded or single-stranded DNA. These results demonstrate that the dprB product plays important roles affecting inter- and intragenomic recombination. We provide evidence that the two putative H. pylori HJRs (DprB and RuvC) have overlapping but distinct functions involving intergenomic (primarily DprB) and intragenomic (primarily RuvC) recombination.
对于自然感受态微生物，如幽门螺杆菌，允许外源DNA重组的步骤尚未完全了解。在促进高频自然转化的幽门螺杆菌基因（dprA）的紧邻下游是HP0334（dprB），注释为假定的霍利迪连接体解离酶（HJR）。我们发现HP0334（dprB）基因产物促进高频自然转化。我们通过遗传分析确定了DprB的生理作用。DprB控制体外生长、暴露于紫外线或氟喹诺酮后的存活以及基因组内重组。dprB ruvC双缺失显著降低同源和异源转化以及暴露于DNA损伤剂后的存活率。此外，DprB蛋白与合成的霍利迪连接体结构结合，而不是与双链或单链DNA结合。这些结果表明dprB产物在影响基因组间和基因组内重组方面发挥重要作用。我们提供的证据表明，两种假定的幽门螺杆菌HJR（DprB和RuvC）具有重叠但不同的功能，涉及基因组间（主要是DprB）和基因组内（主要是RuvC）重组。
