title: In vitro and in vivo characterization of a Mycobacterium tuberculosis mutant deficient in glycosyltransferase Rv1500.
abstract: In Mycobacterium marinum, the homologue of Rv1500 of M. tuberculosis encodes a glycosyltransferase. Initially, it was suggested that this gene is involved in the synthesis of phosphatidylinositol mannosides (PIMs), generating Ac(2)PIM(7) from Ac(2)PIM(5). Phosphatidylinositol mannoside and its related compounds lipomannan (LM) and lipoarabinomannan (LAM) have been shown to modulate the host response to an infection with M. tuberculosis. Here, we generated a deletion mutant of Rv1500 in M. tuberculosis H37Rv, and analyzed the mutant using a biochemical approach as well as in vitro and in vivo infection models. Inactivation of Rv1500 did not lead to an altered expression pattern of PIMs in M. tuberculosis H37Rv. We found phosphatidylinositol (PI), PIM(2), AcPIM(2), Ac(2)PIM(2), and AcPIM(6) in both strains, but were unable to detect Ac(2)PIM(7) or Ac(2)PIM(5) either in the wild type or the mutant strain. Uptake and growth of H37Rv and Rv1500 mutant strains in murine bone marrow-derived macrophages was identical, and TNFalpha and IL-12p40 production in mouse macrophages and dendritic cells was induced to similar levels following infection with either strain. Aerosol challenge of mice showed that wild type and Rv1500 mutant strains had identical growth rates in infected organs over time. We verified mRNA expression of Rv1500 in H37Rv and conclude that Rv1500 must serve a redundant role in viability and virulence of M. tuberculosis.
authors.affiliation: Department of Medical Microbiology and Hospital Epidemiology, Medical School Hannover, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Malm
authors.forename: Kerstin
authors.initials: K
authors.lastname: Walter
authors.forename: Regina
authors.initials: R
authors.lastname: Engel
authors.forename: Silvia
authors.initials: S
authors.lastname: Maass
authors.forename: Stefanie
authors.initials: S
authors.lastname: Pfau
authors.forename: Göran
authors.initials: G
authors.lastname: Hübner
authors.forename: Buko
authors.initials: B
authors.lastname: Lindner
authors.forename: Otto
authors.initials: O
authors.lastname: Holst
authors.forename: Stefan
authors.initials: S
authors.lastname: Ehlers
authors.forename: Franz-Christoph
authors.initials: FC
authors.lastname: Bange
mesh_terms: D000818:Animals; D003713:Dendritic Cells / Q000276:immunology; D005260:Female; D017353:Gene Deletion; D016695:Glycosyltransferases / Q000235:genetics* / Q000378:metabolism*; D053762:Interleukin-12 Subunit p40 / Q000096:biosynthesis; D008264:Macrophages / Q000276:immunology / Q000382:microbiology; D051379:Mice; D009169:Mycobacterium tuberculosis / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity*; D010716:Phosphatidylinositols / Q000032:analysis; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis; D014774:Virulence
chemical_list: D053762:Interleukin-12 Subunit p40; D010716:Phosphatidylinositols; D014409:Tumor Necrosis Factor-alpha; C034154:phosphatidylinositol mannoside; D016695:Glycosyltransferases