title: The Membrane Protein LasM Promotes the Culturability ofLegionella pneumophilain Water.
abstract: The water-borne pathogenLegionella pneumophila (Lp)strongly expresses thelpg1659gene in water. This gene encodes a hypothetical protein predicted to be a membrane protein usingin silicoanalysis. While no conserved domains were identified in Lpg1659, similar proteins are found in manyLegionellaspecies and other aquatic bacteria. RT-qPCR showed thatlpg1659is positively regulated by the alternative sigma factor RpoS, which is essential forLpto survive in water. These observations suggest an important role of this novel protein in the survival ofLpin water. Deletion oflpg1659did not affect cell morphology, membrane integrity or tolerance to high temperature. Moreover,lpg1659was dispensable for growth ofLpin rich medium, and during infection of the amoebaAcanthamoeba castellaniiand of THP-1 human macrophages. However, deletion oflpg1659resulted in an early loss of culturability in water, while over-expression of this gene promoted the culturability ofLp. Therefore, these results suggest thatlpg1659is required forLpto maintain culturability, and possibly long-term survival, in water. Since the loss of culturability observed in the absence of Lpg1659 was complemented by the addition of trace metals into water, this membrane protein is likely a transporter for acquiring essential trace metal for maintaining culturability in water and potentially in other metal-deprived conditions. Given its role in the survival ofLpin water, Lpg1659 was named LasM forLegionellaaquatic survival membrane protein.
authors.affiliation: Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University Montreal, QC, Canada.
authors.forename: Laam
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University Montreal, QC, Canada.
authors.forename: Sébastien P
authors.initials: SP
authors.lastname: Faucher
mesh_terms: D048248:Acanthamoeba castellanii / Q000382:microbiology; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002460:Cell Line / Q000382:microbiology; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D016952:Legionella pneumophila / Q000166:cytology / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D007877:Legionnaires' Disease / Q000382:microbiology; D008264:Macrophages / Q000382:microbiology; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism*; D009154:Mutation; D011401:Promoter Regions, Genetic; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism; D013534:Survival; D016019:Survival Analysis; D013696:Temperature; D000071436:Thermotolerance; D014131:Trace Elements / Q000378:metabolism; D014867:Water; D014871:Water Microbiology
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins; D012808:Sigma Factor; D014131:Trace Elements; C069567:sigma factor KatF protein, Bacteria; D014867:Water
keywords: Legionella pneumophila; freshwater; lpg1659; membrane protein; metal transporter; survival