title: A Mycobacterium avium subsp. paratuberculosis LuxR regulates cell envelope and virulence.
abstract: Mycobacterium avium subsp. paratuberculosis adapts to the environment via the regulation of genes affecting its envelope's composition. Bacteria grown in milk (in vivo conditions) presented differences in the cell wall-associated lipids and in the expression of genes involved in lipid metabolism (FadE8, FadE6 and MAP1420) and host cell invasion (MAP1203, LprL). A different lipid profile was also observed in the envelope of intracellular bacteria after 1 h of infection. Intracellular bacteria showed up-regulation of a LuxR regulator which controls the envelope's composition by up-regulation of FadE8, MAP1420, MAP1203 and LprL and by down-regulation of pks12, mmpL2 and MAP2594. A LuxR-overexpressing strain with a lipid-deficient envelope phenotype, infected epithelial cells more efficiently than the wild-type bacteria; however, it was not more resistant than the wild-type strain to the action of bactericidal proteins. Here we show that LuxR regulates virulence determinants and is involved in mycobacteria adaptation to the host.
authors.affiliation: Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, Oregon 97331, USA.
authors.forename: Marta
authors.initials: M
authors.lastname: Alonso-Hearn
authors.forename: Torsten M
authors.initials: TM
authors.lastname: Eckstein
authors.forename: Sandra
authors.initials: S
authors.lastname: Sommer
authors.forename: Luiz E
authors.initials: LE
authors.lastname: Bermudez
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002417:Cattle; D002460:Cell Line; D002473:Cell Wall / Q000737:chemistry; D003470:Culture Media; D004269:DNA, Bacterial / Q000096:biosynthesis / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics; D008055:Lipids / Q000737:chemistry; D046228:Microarray Analysis; D008892:Milk / Q000382:microbiology; D016927:Mycobacterium avium subsp. paratuberculosis / Q000187:drug effects / Q000235:genetics* / Q000472:pathogenicity*; D010455:Peptides / Q000494:pharmacology; D012329:RNA, Bacterial / Q000096:biosynthesis / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics* / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D015534:Trans-Activators / Q000235:genetics* / Q000502:physiology*; D014158:Transcription, Genetic; D014774:Virulence
chemical_list: D000900:Anti-Bacterial Agents; D003470:Culture Media; D004269:DNA, Bacterial; D008055:Lipids; D010455:Peptides; D012329:RNA, Bacterial; D012097:Repressor Proteins; D015534:Trans-Activators; C064778:LuxR autoinducer binding proteins