The small regulatory RNA Lpr10 regulates the expression of RpoS in <i>Legionella pneumophila</i>

Saoud, Joseph; Carrier, Marie-Claude; Massé, Éric; Faucher, Sébastien P.

doi:10.1111/mmi.14644

Cited by 4 publications

(6 citation statements)

References 77 publications

(133 reference statements)

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“…Thus, RpoE, RpoHII, and StsR form a negative feed-back loop consisting of protein regulators and sRNA. Such regulatory loops have been reported for other bacteria (e.g., [ 51 , 52 , 53 , 54 ]). Regulation in the RpoE-RpoHII-StsR loop is based on different mechanisms.…”

Section: Discussionsupporting

confidence: 74%

A Complex Network of Sigma Factors and sRNA StsR Regulates Stress Responses in R. sphaeroides

Eisenhardt

Remes

Grützner

et al. 2021

IJMS

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Adaptation of bacteria to a changing environment is often accompanied by remodeling of the transcriptome. In the facultative phototroph Rhodobacter sphaeroides the alternative sigma factors RpoE, RpoHI and RpoHII play an important role in a variety of stress responses, including heat, oxidative stress and nutrient limitation. Photooxidative stress caused by the simultaneous presence of chlorophylls, light and oxygen is a special challenge for phototrophic organisms. Like alternative sigma factors, several non-coding sRNAs have important roles in the defense against photooxidative stress. RNAseq-based transcriptome data pointed to an influence of the stationary phase-induced StsR sRNA on levels of mRNAs and sRNAs with a role in the photooxidative stress response. Furthermore, StsR also affects expression of photosynthesis genes and of genes for regulators of photosynthesis genes. In vivo and in vitro interaction studies revealed that StsR, that is under control of the RpoHI and RpoHII sigma factors, targets rpoE mRNA and affects its abundance by altering its stability. RpoE regulates expression of the rpoHII gene and, consequently, expression of stsR. These data provide new insights into a complex regulatory network of protein regulators and sRNAs involved in defense against photooxidative stress and the regulation of photosynthesis genes.

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Section: Discussionsupporting

confidence: 74%

A Complex Network of Sigma Factors and sRNA StsR Regulates Stress Responses in R. sphaeroides

Eisenhardt

Remes

Grützner

et al. 2021

IJMS

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“…The identity of involved transcription regulator(s) remains unknown, although RpoN has been implicated (Sahr et al, 2012; Studholme & Buck, 2000). Additionally, it has recently been proposed that cellular levels of RpoS are under post‐transcriptional control by sRNA Lrp10 in the form of a negative feedback mechanism (Saoud et al 2021). This study suggests the presence of two additional transcription start sites (TSS3 and TSS4) further upstream, with one under the control of RpoS.…”

Section: Discussionmentioning

confidence: 99%

Autorepressor PsrA is required for optimal Legionella pneumophila growth in Acanthamoeba castellanii protozoa

Graham

Patel

Tanner

et al. 2021

Molecular Microbiology

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Legionella pneumophila is a facultative intracellular parasite of freshwater protozoa that undergoes a complex multiphasic lifecycle (Mondino et al., 2020;Newton et al., 2010). Two major morphological forms feature predominantly: a replicative rod-shaped form and a motile coccoid-shaped mature intracellular form (MIF) developed upon egress from the spent protozoan host (Garduño et al., 2002;Greub & Raoult, 2003;Robertson et al., 2014). This MIF (henceforth referred to as cyst form) features distinct ultrastructural characteristics (thickened cell wall, multilayer membrane laminations, poly-3-hydroxybutyrate [PHB] inclusions) ideal for long-term survival between protozoan hosts (Faulkner & Garduño, 2002). It is currently viewed that inhalation of aerosolized cyst-laden water droplets by a susceptible individual leads to infection of alveolar macrophages and manifestation of Legionnaires' disease.Successful infection of protozoa and macrophages by L. pneumophila is enabled by the Dot/Icm Type IV Secretion System (T4SS) which translocates >300 effector proteins into the host cell to manipulate diverse cellular processes (Burstein et al., 2016;Finsel & Hilbi, 2015;Gomez-Valero et al., 2019). In macrophages, the main targets include abrogation of the phagosome-lysosome fusion pathway and

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“…L. pneumophila utilizes a complex regulatory network to sense its vation that a single cis encoded sRNA affects regulatory control (Graham et al, 2021;Saoud et al, 2021a).…”

Section: Con Cluding Remark Smentioning

confidence: 99%

“…Conversely, ppGpp enhances rpoS transcription (Dalebroux et al, 2010b). Presently, little else is known about what regulates rpoS expression, although recent evidence indicates a role for post‐transcriptional regulation via novel noncoding RNA (ncRNA) Lpr10 (Saoud et al., 2021a).…”

Section: Regulatory Mechanisms That Control Cell Differentiationmentioning

confidence: 99%

Molecular regulation of virulence in Legionella pneumophila

Graham,

MacMartin,

de Kievit

et al. 2023

Molecular Microbiology

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Legionella pneumophila is a gram‐negative bacteria found in natural and anthropogenic aquatic environments such as evaporative cooling towers, where it reproduces as an intracellular parasite of cohabiting protozoa. If L. pneumophila is aerosolized and inhaled by a susceptible person, bacteria may colonize their alveolar macrophages causing the opportunistic pneumonia Legionnaires' disease. L. pneumophila utilizes an elaborate regulatory network to control virulence processes such as the Dot/Icm Type IV secretion system and effector repertoire, responding to changing nutritional cues as their host becomes depleted. The bacteria subsequently differentiate to a transmissive state that can survive in the environment until a replacement host is encountered and colonized. In this review, we discuss the lifecycle of L. pneumophila and the molecular regulatory network that senses nutritional depletion via the stringent response, a link to stationary phase‐like metabolic changes via alternative sigma factors, and two‐component systems that are homologous to stress sensors in other pathogens, to regulate differentiation between the intracellular replicative phase and more transmissible states. Together, we highlight how this prototypic intracellular pathogen offers enormous potential in understanding how molecular mechanisms enable intracellular parasitism and pathogenicity.

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The small regulatory RNA Lpr10 regulates the expression of RpoS in Legionella pneumophila

Cited by 4 publications

References 77 publications

A Complex Network of Sigma Factors and sRNA StsR Regulates Stress Responses in R. sphaeroides

A Complex Network of Sigma Factors and sRNA StsR Regulates Stress Responses in R. sphaeroides

Autorepressor PsrA is required for optimal Legionella pneumophila growth in Acanthamoeba castellanii protozoa

Molecular regulation of virulence in Legionella pneumophila

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