title: The RpoH-mediated stress response in Neisseria gonorrhoeae is regulated at the level of activity.
abstract: The general stress response in Neisseria gonorrhoeae was investigated. Transcriptional analyses of the genes encoding the molecular chaperones DnaK, DnaJ, and GrpE suggested that they are transcribed from sigma32 (RpoH)-dependent promoters upon exposure to stress. This was confirmed by mutational analysis of the sigma32 promoter of dnaK. The gene encoding the gonococcal RpoH sigma factor appears to be essential, as we could not isolate viable mutants. Deletion of an unusually long rpoH leader sequence resulted in elevated levels of transcription, suggesting that this region is involved in negative regulation of RpoH expression during normal growth. Transcriptional analyses and protein studies determined that regulation of the RpoH-mediated stress response is different from that observed in most other species, in which regulation occurs predominantly at the transcriptional and translational levels. We suggest that an increase in the activity of preformed RpoH is primarily responsible for induction of the stress response in N. gonorrhoeae.
authors.affiliation: Department of Microbiology, Monash University, Clayton Campus, Victoria 3800, Australia. john.davies@med.monash.edu.au.
authors.forename: Lina
authors.initials: L
authors.lastname: Laskos
authors.forename: Catherine S
authors.initials: CS
authors.lastname: Ryan
authors.forename: Janet A M
authors.initials: JA
authors.lastname: Fyfe
authors.forename: John K
authors.initials: JK
authors.lastname: Davies
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D015964:Gene Expression Regulation, Bacterial; D006360:Heat-Shock Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018869:Heat-Shock Response; D018832:Molecular Chaperones / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009344:Neisseria gonorrhoeae / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D011401:Promoter Regions, Genetic; D017422:Sequence Analysis, DNA; D012808:Sigma Factor / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D012808:Sigma Factor; C069774:heat-shock sigma factor 32