Mutations in AcrR and RNA Polymerase Confer High-Level Resistance to Psoralen-UVA Irradiation
Mutations in AcrR and RNA Polymerase Confer High-Level Resistance to Psoralen-UVA Irradiation
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DOI：
10.1128/jb.00126-23
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发表时间：
2023-05-30
影响因子：
3.2
通讯作者：
Courcelle，Justin
中科院分区：
文献类型：
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作者：
Worley，Travis K.;Weber，Emma A.;Courcelle，Justin
DNA链间交联，如由peptien-UVA照射形成的那些，在人类和细菌中都是高毒性损伤，其中单个损伤在大肠杆菌中是致命的。尽管缺乏有效的修复，但人类癌症和细菌可以对交联治疗产生耐药性，尽管耐药性的机制仍然不清楚。在这里，我们将E。将大肠杆菌暴露于重复的peptien-UVA暴露，以分离三种独立衍生的菌株，其对该处理的抗性比亲本菌株高> 10，000倍。对这些菌株的分析确定了转录调节因子AcrR和RNA聚合酶α亚基的功能获得性突变，这些突变共同导致了这些菌株的耐药性。由AcrR突变赋予的抗性至少部分地通过调节AcrAB-TolC外排泵来介导。通过RNA聚合酶α亚基突变产生的耐药性是通过一种尚未表征的机制发生的，该机制与AcrR突变具有累加效应。两种突变均减少了体内交联的形成。我们讨论了潜在的机制有关的能力，以修复和生存interstrand DNA cross-links. IMPORTANCEPLEMIEN DNA interstrand cross-links是具有抗菌和抗癌特性的高毒性病变。尽管缺乏有效的修复机制，但细胞可以通过仍然不清楚的机制对交联剂产生抗性。我们获得了耐药突变体，并确定了AcrR和RNA聚合酶α亚基中的两个功能获得性突变赋予了对大肠杆菌的高水平抗性。大肠杆菌经pH-UVA处理。AcrR突变通过调节AcrAB-TolC外排泵产生耐药性，与RNA聚合酶突变具有叠加效应，通过减少体内交联的形成发挥作用，并揭示了细胞处理这些环境和临床重要试剂的新机制。
DNA interstrand cross-links, such as those formed by psoralen-UVA irradiation, are highly toxic lesions in both humans and bacteria, with a single lesion being lethal in Escherichia coli. Despite the lack of effective repair, human cancers and bacteria can develop resistance to cross-linking treatments, although the mechanisms of resistance remain poorly defined. Here, we subjected E. coli to repeated psoralen-UVA exposure to isolate three independently derived strains that were >10,000-fold more resistant to this treatment than the parental strain. Analysis of these strains identified gain-of-function mutations in the transcriptional regulator AcrR and the alpha subunit of RNA polymerase that together could account for the resistance of these strains. Resistance conferred by the AcrR mutation is mediated at least in part through the regulation of the AcrAB-TolC efflux pump. Resistance via mutations in the alpha subunit of RNA polymerase occurs through a still-uncharacterized mechanism that has an additive effect with mutations in AcrR. BothacrRandrpoAmutations reduced cross-link formationin vivo. We discuss potential mechanisms in relation to the ability to repair and survive interstrand DNA cross-links.IMPORTANCEPsoralen DNA interstrand cross-links are highly toxic lesions with antimicrobial and anticancer properties. Despite the lack of effective mechanisms for repair, cells can become resistant to cross-linking agents through mechanisms that remain poorly defined. We derived resistant mutants and identified that two gain-of-function mutations in AcrR and the alpha subunit of RNA polymerase confer high levels of resistance to E. coli treated with psoralen-UVA. Resistance conferred by AcrR mutations occurs through regulation of the AcrAB-TolC efflux pump, has an additive effect with RNA polymerase mutations, acts by reducing the formation of cross-linksin vivo, and reveals a novel mechanism by which these environmentally and clinically important agents are processed by the cell.