Novel regulation targets of the metal-response BasS-BasR two-component system of Escherichia coli
Novel regulation targets of the metal-response BasS-BasR two-component system of Escherichia coli
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DOI：
10.1099/mic.0.057745-0
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发表时间：
2012-06-01
期刊：
影响因子：
2.8
通讯作者：
Ishihama, Akira
中科院分区：
文献类型：
--
作者：
Ogasawara, Hiroshi;Shinohara, Shota;Ishihama, Akira
在大肠杆菌中，BasS-BasR双组分系统被认为是一种铁和锌感应转录调节剂，但到目前为止，只有少数基因被鉴定为受磷酸化BasR的直接控制。使用基因组SELEX（配体的系统进化通过指数富集）筛选，我们已经在大肠杆菌基因组上确定了至少38个磷酸化BasR结合位点，并基于BasR结合位点预测了20多个新的调控靶点。通过对高亲和BasR结合位点的DNase I足迹分析，鉴定出TTAAnnTT序列的直接重复序列为BasR盒。通过对野生型大肠杆菌和其他等基因basR缺失突变体的靶基因mrna进行Northern blot分析，证实了靶基因在体内的转录调节作用。BasR调控子可分为三组基因：第一组包括膜结构形成和修饰的基因；第2组包括调节膜功能的基因；第3组包括应激细胞功能基因，包括csgD，生物膜形成的主要调控因子。
The BasS-BasR two-component system is known as an iron- and zinc-sensing transcription regulator in Escherichia coli, but so far only a few genes have been identified to be under the direct control of phosphorylated BasR. Using Genomic SELEX (systematic evolution of ligands by exponential enrichment) screening, we have identified a total of at least 38 binding sites of phosphorylated BasR on the E. coli genome, and based on the BasR-binding sites, have predicted more than 20 novel targets of regulation. By DNase I footprint analysis for high-affinity BasR-binding sites, a direct repeat of a TTAAnnTT sequence was identified as the BasR box. Transcription regulation in vivo of the target genes was confirmed after Northern blot analysis of target gene mRNAs from both wild-type E. coli and an otherwise isogenic basR deletion mutant. The BasR regulon can be classified into three groups of genes: group 1 includes the genes for the formation and modification of membrane structure; group 2 includes genes for modulation of membrane functions; and group 3 includes genes for stress-response cell functions, including csgD, the master regulator of biofilm formation.