The SloR metalloregulator is involved in the Streptococcus mutans oxidative stress response.
The SloR metalloregulator is involved in the Streptococcus mutans oxidative stress response.
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DOI：
10.1111/omi.12147
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发表时间：
2016-12
影响因子：
3.7
通讯作者：
Spatafora GA
中科院分区：
文献类型：
--
作者：
Crepps SC;Fields EE;Galan D;Corbett JP;Von Hasseln ER;Spatafora GA
变形链球菌中一个25kDa的SloR金属调节蛋白调节多种基因的表达，包括编码必需Mn2+运输的sloABC操纵子和促进龋齿发生的基因。在这项研究中，我们报道了变形链球菌的SloC和slor缺陷菌株（分别为GMS284和GMS584），在链霉素和/或生长竞争实验中，与它们的UA159野生型祖菌株和它们的互补菌株（分别为GMS285和GMS585）相比，它们的存活率受到损害。链霉素检测结果显示，GMS584的抑制区明显大于UA159或GMS585，这表明在没有SloR的情况下，变形链球菌的生存能力减弱。竞争分析显示，GMS284和GMS584与SloC和slor的对应物相比，在过氧化物挑战中的生存能力受到损害。这些发现与SloC和SloR在变形链球菌耐氧性中的作用一致。我们还预测了GMS584与UA159和GMS585在有氧生长时氧化应激耐受基因的差异表达。qRT-PCR实验结果显示，与UA159和GMS585相比，GMS584中S. mutans sod、tpx和sloC的表达上调，说明氧化应激对S. mutans的影响在SloR缺失时比在SloR存在时更严重。电泳迁移率转移试验的结果表明，SloR不直接结合sod或tpx启动子区域，这意味着可能存在中介体来仲裁SloR对氧化应激的反应。
A 25kDa SloR metalloregulatory protein in Streptococcus mutans modulates the expression of multiple genes, including the sloABC operon that encodes essential Mn2+ transport and genes that promote cariogenesis. In this study, we report on SloC- and SloR-deficient strains of S. mutans (GMS284 and GMS584, respectively) that demonstrate compromised survivorship compared to their UA159 wildtype progenitor and their complemented strains (GMS285 and GMS585, respectively), when challenged with streptonigrin and/or in growth competition experiments. The results of streptonigrin assays revealed significantly larger zones of inhibition for GMS584 than for either UA159 or GMS585, indicating weakened S. mutans survivorship in the absence of SloR. Competition assays revealed a compromised ability for GMS284 and GMS584 to survive peroxide challenge compared with their SloC- and SloR-proficient counterparts. These findings are consistent with a role for SloC and SloR in S. mutans aerotolerance. We also predicted differential expression of oxidative stress tolerance genes in GMS584 versus UA159 and GMS585 when grown aerobically. The results of qRT-PCR experiments revealed S. mutans sod, tpx, and sloC expression that was up-regulated in GMS584 compared to UA159 and GMS585, indicating that the impact of oxidative stress on S. mutans is more severe in the absence of SloR than in its presence. The results of electrophoretic mobility shift assays indicate that SloR does not bind to the sod or tpx promoter regions directly, implicating intermediaries that may arbitrate the SloR response to oxidative stress.