THE MARR REPRESSOR OF THE MULTIPLE ANTIBIOTIC-RESISTANCE (MAR) OPERON IN ESCHERICHIA-COLI - PROTOTYPIC MEMBER OF A FAMILY OF BACTERIAL REGULATORY PROTEINS INVOLVED IN SENSING PHENOLIC-COMPOUNDS
THE MARR REPRESSOR OF THE MULTIPLE ANTIBIOTIC-RESISTANCE (MAR) OPERON IN ESCHERICHIA-COLI - PROTOTYPIC MEMBER OF A FAMILY OF BACTERIAL REGULATORY PROTEINS INVOLVED IN SENSING PHENOLIC-COMPOUNDS
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DOI：
10.1007/bf03401581
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发表时间：
1995-05-01
影响因子：
5.7
通讯作者：
MILLER, PF
中科院分区：
文献类型：
--
作者：
SULAVIK, MC;GAMBINO, LF;MILLER, PF
背景：大肠埃希菌的marr基因编码一个marrab操纵子的抑制子，该操纵子是控制多重抗生素耐药的一个调节位。MARR的失活导致MARA离子的表达增加，它作用于细胞中的几个目标基因，从而减少抗生素的积累。大肠杆菌暴露在水杨酸钠(SAL)诱导marrab操纵子转录和抗生素耐药性。SAL拮抗MarR阻遏活性的机制尚不清楚。材料和方法：将重组质粒库引入一株报告菌株，以鉴定编码MarR阻遏活性的克隆基因。序列数据库的计算机分析也被用来搜索与MarR相关的蛋白质。结果：鉴定出第二个具有抑制活性的大肠杆菌基因MprA。随后的数据库搜索显示，来自各种细菌的10个蛋白质家族与MarR和MprA具有显著的氨基酸序列相似性。这些蛋白中至少有4个是转录抑制因子，其活性可被SAL或结构上与SAL相关的酚类物质所拮抗。结论：MARR家族是一组调节因子，其活性是以酚类化合物的形式响应环境信号而被调节的。其中许多药物都是从植物中提取的。一些MARR同系物似乎更有可能控制在动物宿主中表达的系统，这表明细菌对酚类的感知在各种环境中和在许多过程的调节中都是重要的。
Background: The marR gene of Escherichia coli encodes a repressor of the marRAB operon, a regulatory locus controlling multiple antibiotic resistance in this ore:anism. Inactivation of marR results in increased express;ion of marA, which acts at several target genes in the cell leading to reduced antibiotic accumulation. Exposure of E. coli to sodium salicylate (SAL) induces marRAB operon transcription and antibiotic resistance. The mechanism by which SAL antagonizes MarR repressor activity is unclear.Materials and Methods: Recombinant plasmid libraries were introduced into a reporter strain designed to identify cloned genes encoding MarR repressor activity. Computer analysis of sequence databases was also used to search for proteins related to MarR.Results: A second E. coli gene, MprA, that exhibits repressor activity was identified. Subsequent database searching revealed a family of 10 proteins from a variety of bacteria that share significant amino acid sequence similarity to MarR and MprA. At least four of these proteins are transcriptional repressors whose activity is antagonized by SAL or by phenolic agents structurally related to SAL.Conclusions: The MarR family is identified as a group of regulatory factors whose activity is modulated in response to environmental signals in the form of phenolic compounds. Many of these agents are plant derived. Some of the MarR homologs appear more likely to control systems expressed in animal hosts, suggesting that phenolic sensing by bacteria is important in a variety of environments and in the regulation of numerous processes.