The MarR-Type Regulator PA3458 Is Involved in Osmoadaptation Control in Pseudomonas aeruginosa
Karolina Kotecka1, Adam Kawalek1, Kamil Kobylecki1
1Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland.
Abstract:
Pseudomonas aeruginosa is a facultative human pathogen, causing acute and chronic infections that are especially dangerous for immunocompromised patients. The eradication of P. aeruginosa is difficult due to its intrinsic antibiotic resistance mechanisms, high adaptability, and genetic plasticity. The bacterium possesses multilevel regulatory systems engaging a huge repertoire of transcriptional regulators (TRs). Among these, the MarR family encompasses a number of proteins, mainly acting as repressors, which are involved in response to various environmental signals. In this work, we aimed to decipher the role of PA3458, a putative MarR-type TR from P. aeruginosa. Transcriptional profiling of P. aeruginosa PAO1161 overexpressing PA3458 showed changes in the mRNA level of 133 genes; among them, 100 were down-regulated, suggesting the repressor function of PA3458. Concomitantly, ChIP-seq analysis identified more than 300 PA3458 binding sites in P. aeruginosa. The PA3458 regulon encompasses genes involved in stress response, including the PA3459-PA3461 operon, which is divergent to PA3458. This operon encodes an asparagine synthase, a GNAT-family acetyltransferase, and a glutamyl aminopeptidase engaged in the production of N-acetylglutaminylglutamine amide (NAGGN), which is a potent bacterial osmoprotectant. We showed that PA3458-mediated control of PA3459-PA3461 expression is required for the adaptation of P. aeruginosa growth in high osmolarity. Overall, our data indicate that PA3458 plays a role in osmoadaptation control in P. aeruginosa.
Insights
Pseudomonas aeruginosa uses the transcriptional regulator PA3458 to control genes involved in osmoadaptation. This protein helps the bacterium adapt to high osmolarity environments by regulating osmoprotectant production.
Area of Science:
- Microbiology
- Molecular Biology
- Bacterial Pathogenesis
Background:
- Pseudomonas aeruginosa is a resilient pathogen causing difficult-to-treat infections, particularly in immunocompromised individuals.
- Its adaptability stems from intrinsic antibiotic resistance and complex regulatory systems involving numerous transcriptional regulators (TRs).
- The MarR family of TRs, often acting as repressors, responds to diverse environmental cues.
Purpose of the Study:
- To investigate the function of PA3458, a putative MarR-type TR in Pseudomonas aeruginosa.
- To elucidate the role of PA3458 in bacterial adaptation and gene regulation.
Main Methods:
- Transcriptional profiling (mRNA analysis) of P. aeruginosa overexpressing PA3458.
- Chromatin immunoprecipitation sequencing (ChIP-seq) to identify PA3458 binding sites.
- Analysis of gene expression changes and bacterial growth under varying osmolarity conditions.
Main Results:
- Overexpression of PA3458 led to differential expression of 133 genes, with 100 down-regulated, indicating a repressor function.
- ChIP-seq identified over 300 binding sites for PA3458.
- PA3458 regulates the PA3459-PA3461 operon, essential for producing the osmoprotectant N-acetylglutaminylglutamine amide (NAGGN).
- PA3458-mediated regulation of this operon is crucial for P. aeruginosa adaptation to high osmolarity.
Conclusions:
- PA3458 acts as a repressor involved in the osmoadaptation of Pseudomonas aeruginosa.
- The study reveals a novel regulatory pathway controlling bacterial response to osmotic stress.
Related Concept Videos
01:28Global Regulatory Systems
01:30Other Stress Responses in Bacteria
01:23Operon Model
01:28Gene Regulation in Microbial Communities: Quorum Sensing
01:47Osmoregulation in Insects
01:21Repressible Operon: trp Operon