Dataset Information

The Legionella pneumophila kai operon is implicated in stress response and confers fitness in competitive environments.

ABSTRACT: Legionella pneumophila uses aquatic protozoa as replication niche and protection from harsh environments. Although L.?pneumophila is not known to have a circadian clock, it encodes homologues of the KaiBC proteins of Cyanobacteria that regulate circadian gene expression. We show that L.?pneumophila kaiB, kaiC and the downstream gene lpp1114, are transcribed as a unit under the control of the stress sigma factor RpoS. KaiC and KaiB of L.?pneumophila do not interact as evidenced by yeast and bacterial two-hybrid analyses. Fusion of the C-terminal residues of cyanobacterial KaiB to Legionella?KaiB restores their interaction. In contrast, KaiC of L.?pneumophila conserved autophosphorylation activity, but KaiB does not trigger the dephosphorylation of KaiC like in Cyanobacteria. The crystal structure of L.?pneumophila?KaiB suggests that it is an oxidoreductase-like protein with a typical thioredoxin fold. Indeed, mutant analyses revealed that the kai operon-encoded proteins increase fitness of L.?pneumophila in competitive environments, and confer higher resistance to oxidative and sodium stress. The phylogenetic analysis indicates that L.?pneumophila?KaiBC resemble Synechosystis?KaiC2B2 and not circadian KaiB1C1. Thus, the L.?pneumophila?Kai proteins do not encode a circadian clock, but enhance stress resistance and adaption to changes in the environments.

SUBMITTER: Loza-Correa M

PROVIDER: S-EPMC4113418 | biostudies-literature | 2014 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

The Legionella pneumophila kai operon is implicated in stress response and confers fitness in competitive environments.

Loza-Correa Maria M Sahr Tobias T Rolando Monica M Daniels Craig C Petit Pierre P Skarina Tania T Gomez Valero Laura L Dervins-Ravault Delphine D Honoré Nadine N Savchenko Aleksey A Buchrieser Carmen C

Environmental microbiology 20130819 2

Legionella pneumophila uses aquatic protozoa as replication niche and protection from harsh environments. Although L. pneumophila is not known to have a circadian clock, it encodes homologues of the KaiBC proteins of Cyanobacteria that regulate circadian gene expression. We show that L. pneumophila kaiB, kaiC and the downstream gene lpp1114, are transcribed as a unit under the control of the stress sigma factor RpoS. KaiC and KaiB of L. pneumophila do not interact as evidenced by yeast and bacte ...[more]

PMID: 23957615

Similar Datasets

Project description:ABSTRACT Integrative conjugative elements (ICEs) are mobile blocks of DNA that can contribute to bacterial evolution by self-directed transmission of advantageous traits. Here, we analyze the activity of a putative 65-kb ICE harbored by Legionella pneumophila using molecular genetics, conjugation assays, a phenotype microarray screen, and macrophage infections. The element transferred to a naive L. pneumophila strain, integrated site-specifically, and conferred increased resistance to oxacillin, penicillin, hydrogen peroxide, and bleach. Furthermore, the element increased survival of L. pneumophila within restrictive mouse macrophages. In particular, this ICE protects L. pneumophila from phagocyte oxidase activity, since mutation of the macrophage NADPH oxidase eliminated the fitness difference between strains that carried and those that lacked the mobile element. Renamed ICE-?ox (for ?-lactam antibiotics and oxidative stress), this transposable element is predicted to contribute to the emergence of L. pneumophila strains that are more fit in natural and engineered water systems and in macrophages. IMPORTANCE Bacteria evolve rapidly by acquiring new traits via horizontal gene transfer. Integrative conjugative elements (ICEs) are mobile blocks of DNA that encode the machinery necessary to spread among bacterial populations. ICEs transfer antibiotic resistance and other bacterial survival factors as cargo genes carried within the element. Here, we show that Legionella pneumophila, the causative agent of Legionnaires' disease, carries ICE-?ox, which enhances the resistance of this opportunistic pathogen to bleach and ?-lactam antibiotics. Moreover, L. pneumophila strains encoding ICE-?ox are more resistant to macrophages that carry phagocyte oxidase. Accordingly, ICE-?ox is predicted to increase the fitness of L. pneumophila in natural and engineered waters and in humans. To our knowledge, this is the first description of an ICE that confers oxidative stress resistance to a nosocomial pathogen.

Dataset Information

The Legionella pneumophila kai operon is implicated in stress response and confers fitness in competitive environments.

Publications

The Legionella pneumophila kai operon is implicated in stress response and confers fitness in competitive environments.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets