title: Expression of the mceA, esat-6 and hspX genes in Mycobacterium tuberculosis and their responses to aerobic conditions and to restricted oxygen supply.
abstract: The expression of six of the mammalian cell-entry (mce1a-mce1f) genes of the mce1 operon of Mycobacterium tuberculosis has been described previously. In this study, data are presented for the expression of other mammalian cell-entry homologues (mce-2a, mce-3a and mce-4a) at the RNA level, as determined by RT-PCR. The stress responses of these genes and of other immunologically important antigens are also characterized with respect to the introduction of oxygen depletion. Analysis of the expression of the mceA genes in relation to oxygen depletion revealed that they were expressed differentially. The RT-PCR results showed that mce-1a, mce-2a, hspX (encoding the alpha-crystallin antigen Acr) and esat-6 (encoding the early secretory antigenic target-6) were expressed throughout the cultivation period, whereas the expression of mce-3a and mce-4a was downregulated in the later stages of cultivation. This study gives new insights into the expression profiles of the different mce operons and the hspX and esat-6 genes in an in vitro model of dormant-like bacilli. Identification of the genes that are differentially expressed under aerobic conditions and under oxygen-limited conditions contributes to our understanding of the bacilli involved in latent tuberculosis.
authors.affiliation: Broegelmann Research Laboratory, University of Bergen, Armauer Hansens Hus, N-5021 Bergen, Norway3.|Center for International Health, University of Bergen, Armauer Hansens Hus, N-5021 Bergen, Norway2.|Norwegian Institute of Public Health, PO Box 4404, Nydalen, N-0403 Oslo, Norway1.
authors.forename: Yoseph
authors.initials: Y
authors.lastname: Haile
authors.affiliation: Institute of General Practice and Community Medicine, University of Oslo, PO Box 1130 Blindern, N-0317 Oslo, Norway4.|Center for International Health, University of Bergen, Armauer Hansens Hus, N-5021 Bergen, Norway2.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Bjune
authors.affiliation: Norwegian Institute of Public Health, PO Box 4404, Nydalen, N-0403 Oslo, Norway1.
authors.forename: Harald G
authors.initials: HG
authors.lastname: Wiker
mesh_terms: D000332:Aerobiosis; D000942:Antigens, Bacterial / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003470:Culture Media; D015964:Gene Expression Regulation, Bacterial; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000254:growth & development* / Q000472:pathogenicity / Q000502:physiology*; D010100:Oxygen / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D003470:Culture Media; C093276:ESAT-6 protein, Mycobacterium tuberculosis; C118127:HspX protein, Mycobacterium tuberculosis; D010100:Oxygen