The Institute for Advanced Materials and Nanotechnology, The Mina and Everard Goodman Faculty of Life Sciences, Ramat-Gan, 52900, Israel.
The Institute for Advanced Materials and Nanotechnology, The Mina and Everard Goodman Faculty of Life Sciences, Ramat-Gan, 52900, Israel.
Microbiol Res. 2018 Jan;206:91-98. doi: 10.1016/j.micres.2017.10.004. Epub 2017 Oct 13.
Surface Acoustic Waves (SAW) were previously shown to inhibit biofilm formation, increase bacterial susceptibility to antibiotic treatment and alter the transcription pattern of Pseudomonas aeruginosa. Here we characterize one gene, sawR (PA3133), that is highly overexpressed when P. aeruginosa is exposed to SAW. SawR is a putative transcription factor belonging to the TetR regulator family. When overexpressed sawR causes numerous phenotypes, including the accumulation of a brown pigment which we identified as pyomelanin. In this study we describe how sawR regulates pyomelanin synthesis. We show that sawR down-regulates the expression levels of hmgA and this causes the accumulation of homogentisic acid which in turn undergoes oxidation and polymerization to pyomelanin. Using bioinformatics, we were able to identify a specific amino acid, arginine 23, which is found within the sawR DNA binding domain and is crucial for its regulatory activity. Our results indicate that sawR does not affect any other genes in the phenylalanine/tyrosine metabolic pathway and its repressive ability on hmgA is not mediated by the hmgA repressor PA2010 (i.e. hmgR). Taken together, our results shed light on the regulatory cascade controlling pyomelanin synthesis and uncover yet another unknown regulator involved in its regulation.
声表面波 (SAW) 先前被证明可以抑制生物膜的形成，增加细菌对抗生素治疗的敏感性，并改变铜绿假单胞菌的转录模式。在这里，我们描述了一个基因 sawR (PA3133)，当铜绿假单胞菌暴露于 SAW 时，该基因高度过表达。SawR 是一种假定的转录因子，属于 TetR 调节因子家族。当过度表达 sawR 时，会引起许多表型，包括积累一种棕色色素，我们将其鉴定为焦黑素。在这项研究中，我们描述了 sawR 如何调节焦黑素的合成。我们表明 sawR 下调 hmgA 的表达水平，这导致 homogentisic 酸的积累，homogentisic 酸反过来又会发生氧化和聚合形成焦黑素。通过生物信息学，我们能够鉴定出 sawR DNA 结合域内的一个特定氨基酸，精氨酸 23，它对于其调节活性至关重要。我们的结果表明，sawR 不会影响苯丙氨酸/酪氨酸代谢途径中的任何其他基因，并且其对 hmgA 的抑制能力不是通过 hmgA 抑制剂 PA2010（即 hmgR）介导的。总之，我们的结果阐明了控制焦黑素合成的调节级联，并揭示了另一个参与其调节的未知调节剂。
