GSE163234
The LysR-type transcriptional regulator BsrA (PA2121) is engaged in the control of vital metabolic pathways in Pseudomonas aeruginosa (RNA-seq)
Pseudomonas aeruginosa, a facultative human pathogen causing nosocomial infections, has complex regulatory systems involving many transcriptional regulators. The LTTR family (LysR-Type Transcriptional Regulators) consists of proteins involved in regulation of various processes including stress response, motility, virulence or amino acid metabolism. The aim of this study was characterization of the LysR-type regulator BsrA (PA2121), identified previously as a negative regulator of biofilm formation in P. aeruginosa. To identify the BsrA binding sites in P. aeruginosa the ChIP-seq analysis was performed. It revealed 765 BsrA binding sites in P. aeruginosa PAO1161 genome, among them 367 was localized in the intergenic regions. Parallel transcriptomic analysis identified altered expression of 157 genes in response to BsrA excess, among them 35 had a BsrA binding site in the corresponding promoter regions, indicating direct influence of BsrA on expression of these genes. BsrA-repressed loci encompass genes encoding proteins engaged in key metabolic pathways including the tricarboxylic acid cycle. A group of directly activated genes by BsrA, consists of several loci encoding proteins involved in pili/fimbriae assembly as well as secretion and transport systems. Results also confirmed that BsrA acts as an autorepressor. Presented data uncover the regulon of BsrA protein with its role as transcriptional regulator of genes engaged in vital cellular processes in P. aeruginosa. Overall design: Pseudomonas aeruginosa PAO1161 (leu-, r-, RifR) derivative of PAO1 was used in the experiment (Kawalek et al., 2020; BMC Genomics, 21:14). To determine the impact of an increased BsrA level on the transcriptome, the RNA-seq analysis was performed on RNA isolated from Pseudomonas aeruginosa PAO1161/pMEB63 (lacIQ-tacp-bsrA) cultures grown under selection in L broth with 0.05 mM IPTG (hereafter referred to as BsrA) as well as from Pseudomonas aeruginosa PAO1161 carrying pAMB9.37 (lacIQ-tacp) cells grown under selection in L broth with 0.05 mM IPTG (empty vector control, hereafter called EV). The RNA was isolated from exponentially growing cultures (OD600 0.5). Three independent biological replicates of total RNA were isolated for each strain.