Identification of novel genes that promote persister formation by repressing transcription and cell division in Pseudomonas aeruginosa

• Published in: Journal of antimicrobial chemotherapy 2019-09, Vol.74 (9), p.2575-2587
• Main Authors: Long, Yuqing, Fu, Weixin, Li, Shouyi, Ren, Huan, Li, Mei, Liu, Chang, Zhang, Buyu, Xia, Yushan, Fan, Zheng, Xu, Chang, Liu, Jianfeng, Jin, Yongxin, Bai, Fang, Cheng, Zhihui, Liu, Xiaoyun, Jin, Shouguang, Wu, Weihui
• Format: Article
• Language: English
• ISSN: 0305-7453; 1460-2091
• DOI: 10.1093/jac/dkz214

Abstract Objectives Bacterial persisters are a small subpopulation of cells that are highly tolerant of antibiotics and contribute to chronic and recalcitrant infections. Global gene expression in Pseudomonas aeruginosa persister cells and genes contributing to persister formation remain largely unknown. The objective of this study was to examine the gene expression profiles of the persister cells and those that regained growth in fresh medium, as well as to identify novel genes related to persister formation. Methods P. aeruginosa persister cells and those that regrew in fresh medium were collected and subjected to RNA sequencing analysis. Genes up-regulated in the persister cells were overexpressed to evaluate their roles in persister formation. The functions of the persister-contributing genes were assessed with pulse–chase assay, affinity chromatography, fluorescence and electron microscopy, as well as a light-scattering assay. Results An operon containing PA2282–PA2287 was up-regulated in the persister cells and down-regulated in the regrowing cells. PA2285 and PA2287 play key roles in persister formation. PA2285 and PA2287 were found to bind to RpoC and FtsZ, which are involved in transcription and cell division, respectively. Pulse–chase assays demonstrated inhibitory effects of PA2285 and PA2287 on the overall transcription. Meanwhile, light-scattering and microscopy assays demonstrated that PA2285 and PA2287 interfere with cell division by inhibiting FtsZ aggregation. PA2285 and PA2287 are conserved in pseudomonads and their homologous genes in Pseudomonas putida contribute to persister formation. Conclusions PA2285 and PA2287 are novel bifunctional proteins that contribute to persister formation in P. aeruginosa.