title: Natural transformation occurs independently of the essential actin-like MreB cytoskeleton in Legionella pneumophila.
abstract: Natural transformation is the process by which bacteria can actively take up and integrate exogenous DNA thereby providing a source of genetic diversity. Under specific growth conditions the coordinated expression of several genes--a situation referred to as "competence"--allows bacteria to assemble a highly processive and dedicated system that can import high molecular weight DNA. Within the cell these large imported DNA molecules are protected from degradation and brought to the chromosome for recombination. Here, we report elevated expression of mreB during competence in the Gram-negative pathogen Legionella pneumophila. Interestingly a similar observation had previously been reported in the distantly-related Gram-positive organism Bacillus subtilis. MreB is often viewed as the bacterial actin homolog contributing to bacterial morphogenesis by coordinating peptidoglycan-synthesising complexes. In addition MreB is increasingly found to be involved in a growing number of processes including chromosome segregation and motor-driven motility. Using genetic and pharmacological approaches, we examined the possible role of MreB during natural transformation in L. pneumophila. Our data show that natural transformation does not require MreB dynamics and exclude a direct role of MreB filaments in the transport of foreign DNA and its recombination in the chromosome.
authors.affiliation: CNRS UMR5240 MAP, Villeurbanne, France.|Université Claude Bernard Lyon 1, Villeurbanne, France.
authors.forename: Pierre-Alexandre
authors.initials: PA
authors.lastname: Juan
authors.affiliation: CNRS UMR5240 MAP, Villeurbanne, France.|Université Claude Bernard Lyon 1, Villeurbanne, France.
authors.forename: Laetitia
authors.initials: L
authors.lastname: Attaiech
authors.affiliation: CNRS UMR5240 MAP, Villeurbanne, France.|Université Claude Bernard Lyon 1, Villeurbanne, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Charpentier
mesh_terms: D000199:Actins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D020090:Chromosome Segregation; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism*; D061269:DNA Transformation Competence / Q000187:drug effects; D024881:Drug Resistance, Bacterial / Q000187:drug effects; D005798:Genes, Bacterial; D016952:Legionella pneumophila / Q000378:metabolism*; D009024:Morphogenesis / Q000502:physiology; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D013890:Thiourea / Q000031:analogs & derivatives / Q000494:pharmacology; D015854:Up-Regulation
chemical_list: D000199:Actins; D001426:Bacterial Proteins; C015799:2,6-dichlorobenzylthiopseudourea; D013890:Thiourea