Small regulatory RNAs control the multi-cellular adhesive lifestyle of Escherichia coli
Small regulatory RNAs control the multi-cellular adhesive lifestyle of Escherichia coli
复制标题
DOI：
10.1111/j.1365-2958.2012.07976.x
复制
发表时间：
2012-04-01
影响因子：
3.6
通讯作者：
Valentin-Hansen, Poul
中科院分区：
文献类型：
--
作者：
Jorgensen, Mikkel Girke;Nielsen, Jesper S.;Valentin-Hansen, Poul
小调控RNA分子最近被认为是真核生物和细菌发育过程的重要调控元件。我们在这里描述了一个引人注目的例子，即大肠杆菌，它可以在单细胞运动的生活方式和多细胞、无固定和粘附的状态之间切换，从而使表面形成生物膜。为此，细菌需要对其基因表达进行重新编程，而在许多大肠杆菌和沙门氏菌菌株中，生活方式的转变依赖于控制级联反应，这些级联反应抑制鞭毛表达并激活curli的合成，curli是细胞外粘附纤维，对细胞的共同聚集和粘附到生物和非生物表面很重要。通过结合生物信息学、遗传和生化分析，我们确定了三个小rna，它们通过反义机制下调CsgD的翻译，CsgD是curli合成的主要调节因子。我们的研究表明，这三种RNA的基础表达足以下调CsgD的合成并阻止curli的形成，这表明它们都在curli调控网络中发挥着重要作用。我们的发现为Rcs信号通路如何负调控curli合成提供了第一个线索，并将直接作用于csgD mRNA的小调控rna的数量增加到5个。
Small regulatory RNA molecules have recently been recognized as important regulatory elements of developmental processes in both eukaryotes and bacteria. We here describe a striking example in Escherichia coli that can switch between a single-cell motile lifestyle and a multi-cellular, sessile and adhesive state that enables biofilm formation on surfaces. For this, the bacterium needs to reprogramme its gene expression, and in many E. coli and Salmonella strains the lifestyle shift relies on control cascades that inhibit flagellar expression and activate the synthesis of curli, extracellular adhesive fibres important for co-aggregation of cells and adhesion to biotic and abiotic surfaces. By combining bioinformatics, genetic and biochemical analysis we identified three small RNAs that act by an antisense mechanism to downregulate translation of CsgD, the master regulator of curli synthesis. Our demonstration that basal expression of each of the three RNA species is sufficient to downregulate CsgD synthesis and prevent curli formation indicates that all play a prominent role in the curli regulatory network. Our findings provide the first clue as to how the Rcs signalling pathway negatively regulates curli synthesis and increase the number of small regulatory RNAs that act directly on the csgD mRNA to five.