title: 3-Ketosteroid 9alpha-hydroxylase is an essential factor in the pathogenesis of Mycobacterium tuberculosis.
abstract: Mycobacterium tuberculosis H37Rv contains the kshA (Rv3526) and kshB (Rv3571) genes, encoding 3-ketosteroid 9alpha-hydroxylase (KSH). Consistent with their predicted roles, the DeltakshA and DeltakshB deletion mutants of M. tuberculosis H37Rv were unable to use cholesterol and 4-androstene-3,17-dione as primary carbon and energy sources. Interestingly, DeltakshA and DeltakshB mutants were also unable to metabolize the steroid substrate 5alpha-androstane-3,17-dione, whereas wild-type M. tuberculosis H37Rv could. The deletion of either of these genes lead to rapid death of the microorganism in murine infection models and in macrophages, showing that kshA and kshB are essential factors for M. tuberculosis pathogenesis. Penta-acylated trehalose (PAT) biosynthesis was altered in the DeltakshB mutant, but not the DeltakshA mutant. The DeltakshB mutant synthesizes all other types of lipids. The DeltakshB mutant had a thickened outer layer in its cell wall. KshB thus appears to be involved in multiple processes, probably as a reductase of different oxygenases. We conclude that an impaired 3-ketosteroid 9alpha-hydroxylase activity is the cause of the highly attenuated phenotype of our M. tuberculosis H37Rv mutants.
authors.affiliation: Centre for Infection, Division of Cellular and Molecular Medicine, St George's University of London, London SW17 0RE, UK. ymhu@sgul.ac.uk
authors.forename: Yanmin
authors.initials: Y
authors.lastname: Hu
authors.forename: Robert
authors.initials: R
authors.lastname: van der Geize
authors.forename: Gurdyal S
authors.initials: GS
authors.lastname: Besra
authors.forename: Sudagar S
authors.initials: SS
authors.lastname: Gurcha
authors.forename: Alexander
authors.initials: A
authors.lastname: Liu
authors.forename: Manfred
authors.initials: M
authors.lastname: Rohde
authors.forename: Mahavir
authors.initials: M
authors.lastname: Singh
authors.forename: Anthony
authors.initials: A
authors.lastname: Coates
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D002478:Cells, Cultured; D015169:Colony Count, Microbial; D005260:Female; D017353:Gene Deletion; D008168:Lung / Q000382:microbiology; D008264:Macrophages / Q000382:microbiology; D053858:Metabolic Networks and Pathways; D051379:Mice; D008807:Mice, Inbred BALB C; D050296:Microbial Viability; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000502:physiology*; D009169:Mycobacterium tuberculosis / Q000201:enzymology* / Q000472:pathogenicity*; D013154:Spleen / Q000382:microbiology; D014376:Tuberculosis / Q000382:microbiology; D014774:Virulence; D037521:Virulence Factors / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins; D037521:Virulence Factors; C540657:3-ketosteroid 9alpha-hydroxylase, Mycobacterium tuberculosis; D006899:Mixed Function Oxygenases