The yjbEFGH locus in Escherichia coli K-12 is an operon encoding proteins involved in exopolysaccharide production
The yjbEFGH locus in Escherichia coli K-12 is an operon encoding proteins involved in exopolysaccharide production
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DOI：
10.1099/mic.0.2006/002907-0
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发表时间：
2007-04-01
期刊：
影响因子：
2.8
通讯作者：
Clarke, David J.
中科院分区：
文献类型：
--
作者：
Ferrieres, Lionel;Aslam, Shazia N.;Clarke, David J.
RcsCDB磷酸化中继最初被鉴定为大肠杆菌K-12中大肠杆菌酸生物合成的主要调节剂。然而，最近的转录组学分析已经确定了超过150个属于Rcs调节子的基因，包括yjbE，yjbF，yjbG和yjbH。这些基因聚集在基因组上，并以相同的方向定向，但它们的功能仍然未知。在这项工作中，它表明，yjbE，yjbF，yjbG和yjbH被转录为一个单一的操纵子，它被证实，该操纵子的表达是由Rcs磷酸化继电器控制，在一种依赖于辅助调节蛋白RcsA的方式。有趣的是，北方印迹分析显示，在细胞中的yjbE转录本的量高于yjbEFGH转录本的量，并提出这种差异表达是由yjbE-yjbF基因间区域中存在的强茎环结构介导的。最后，提供的证据表明，yjbEFGH的过表达影响菌落形态，并导致生产的胞外多糖，结合刚果红和甲苯胺蓝-O。
The RcsCDB phosphorelay was originally identified as the main regulator of colanic acid biosynthesis in Escherichia coli K-12. However, recent transcriptomic analyses have identified more than 150 genes belonging to the Rcs regulon, including yjbE, yjbF, yjbG and yjbH. These genes are clustered on the genome and oriented in the same direction but their function remains unknown. In this work it is shown that yjbE, yjbF, yjbG and yjbH are transcribed as a single operon and it is confirmed that the expression of this operon is controlled by the Rcs phosphorelay, in a manner that is dependent on the auxiliary regulatory protein RcsA. Interestingly, Northern blot analysis revealed that the amount of yjbE transcripts in the cell is higher than the amount of yjbEFGH transcripts and it is proposed that this differential expression is mediated by the presence of a strong stem-loop structure in the yjbE-yjbF intergenic region. Finally, evidence is provided that the overexpression of yjbEFGH affects colony morphology and leads to the production of an extracellular polysaccharide that binds Congo red and toluidine blue-O.