Premium
Expression and regulation of the Pseudomonas aeruginosa hibernation promoting factor
Author(s) -
Akiyama Tatsuya,
Williamson Kerry S.,
Franklin Michael J.
Publication year - 2018
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.14001
Subject(s) - biology , rpos , rpon , sigma factor , microbiology and biotechnology , mutant , operon , pseudomonas fluorescens , pseudomonas aeruginosa , messenger rna , gene , gene expression , genetics , promoter , bacteria
Abstract Bacterial biofilms contain subpopulations of cells that are dormant and highly tolerant to antibiotics. While dormant, the bacteria must maintain the integrity of macromolecules required for resuscitation. Previously, we showed that hibernation promoting factor (HPF) is essential for protecting Pseudomonas aeruginosa from ribosomal loss during dormancy. In this study, we mapped the genetic components required for hpf expression. Using 5ʹ‐RACE and fluorescent protein reporter fusions, we show that hpf is expressed as part of the rpoN operon, but that hpf also has a second promoter (P hpf ) within the rpoN gene. P hpf is active when the cells enter stationary phase, and expression from P hpf is modulated, but not eliminated, in mutant strains impaired in stationary phase transition (Δ dksA2 , Δ rpoS and Δ relA/ Δ spoT mutants). The results of reporter gene studies and mRNA folding predictions indicated that the 5ʹ end of the hpf mRNA may also influence hpf expression. Mutations that opened or that stabilized the mRNA hairpin loop structures strongly influenced the amount of HPF produced. The results demonstrate that hpf is expressed independently of rpoN , and that hpf regulation includes both transcriptional and post‐transcriptional processes, allowing the cells to produce sufficient HPF during stationary phase to maintain viability while dormant.