Novel regulators of the csgD gene encoding the master regulator of biofilm formation in Escherichia coli K-12
Novel regulators of the csgD gene encoding the master regulator of biofilm formation in Escherichia coli K-12
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DOI：
10.1099/mic.0.000947
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发表时间：
2020-09-01
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;Ishizuka, Toshiyuki;Ishihama, Akira
在应激条件下，大肠杆菌通过感知各种环境条件形成生物膜以生存。CsgD是生物膜形成的主要调节因子，通过直接调节Curli菌毛的合成来控制细胞聚集。在协议的调节作用，多达14个转录因子（TF）迄今已被确定参与调节的csgD启动子，每个监控特定的环境条件或因素。为了确定这一典型的多因子启动子所涉及的整套TF，我们在本研究中使用一组198个纯化的TF（145个具有已知功能的TF和53个迄今未表征的TF）进行了“启动子特异性转录因子”（PS-TF）体外筛选。共鉴定出48个与csgD启动子探针强结合的TF，包括35个已知TF和13个未表征的TF，称为Y-TF。为了寻找新的调节因子，在这项研究中，我们首先分析了总共七个Y-TF，包括YbiH，YdcI，YhjC，YiaJ，YiaU，YjgJ和YjiR。通过对curli fimbriae形成的分析、LacZ报告基因分析、Northern-blot分析和生物膜形成分析，我们鉴定了csgD启动子的至少两个新的调节子，阻遏子YiaJ（重命名为PlaR）和激活子YhjC（重命名为RcdB）。
Under stressful conditions, Escherichia coli forms biofilm for survival by sensing a variety of environmental conditions. CsgD, the master regulator of biofilm formation, controls cell aggregation by directly regulating the synthesis of Curli fimbriae. In agreement of its regulatory role, as many as 14 transcription factors (TFs) have so far been identified to participate in regulation of the csgD promoter, each monitoring a specific environmental condition or factor. In order to identify the whole set of TFs involved in this typical multi-factor promoter, we performed in this study 'promoter-specific transcription-factor' (PS-TF) screening in vitro using a set of 198 purified TFs (145 TFs with known functions and 53 hitherto uncharacterized TFs). A total of 48 TFs with strong binding to the csgD promoter probe were identified, including 35 known TFs and 13 uncharacterized TFs, referred to as Y-TFs. As an attempt to search for novel regulators, in this study we first analysed a total of seven Y-TFs, including YbiH, YdcI, YhjC, YiaJ, YiaU, YjgJ and YjiR. After analysis of curli fimbriae formation, LacZ-reporter assay, Northern-blot analysis and biofilm formation assay, we identified at least two novel regulators, repressor YiaJ (renamed PlaR) and activator YhjC (renamed RcdB), of the csgD promoter.