title: Mce2R from Mycobacterium tuberculosis represses the expression of the mce2 operon.
abstract: The mce2 operon is one of the four mce operons present in Mycobacterium tuberculosis that encode exported proteins with a probable role in the virulence mechanisms of this bacterium. In the present study we demonstrated that Rv0586, which encodes a putative GntR-like regulator, is part of the mce2 operon. By using a promoter-lacZ fusion approach and bioinformatics tools, we found that Rv0586 represses the expression of Mce2 proteins and of a putative endonuclease IV, encoded by end (Rv0670) gene. For this reason, we have re-named the repressor protein Mce2R. By gel-shift experiments Mce2R binding was determined to be located within the mce2 promoter region. In addition, two FadR-like operator motifs were identified within the promoter regions of both the mce2 operon and the end gene. These motifs overlap putative -10 and -35 promoter boxes. M. tuberculosis carrying mce2 and end promoter-lacZ fusions were used to infect J774 macrophage-like cells. Expression of beta-galactosidase was induced after phagocytocis, suggesting that some cellular factor could be a key component of the molecular switch regulation expression of the mce2 operon. In conclusion, these results add novel evidence of the complex regulation of mce operon expression.
authors.affiliation: Institute of Biotechnology, CICVyA-INTA Castelar, N. Repetto and Los Reseros Hurlingham, Argentina.
authors.forename: María de la Paz
authors.initials: Mde L
authors.lastname: Santangelo
authors.forename: Federico
authors.initials: F
authors.lastname: Blanco
authors.forename: Eleonora
authors.initials: E
authors.lastname: Campos
authors.forename: Marcelo
authors.initials: M
authors.lastname: Soria
authors.forename: María Verónica
authors.initials: MV
authors.lastname: Bianco
authors.forename: Laura
authors.initials: L
authors.lastname: Klepp
authors.forename: Alicia
authors.initials: A
authors.lastname: Alito
authors.forename: Osvaldo
authors.initials: O
authors.lastname: Zabal
authors.forename: Angel
authors.initials: A
authors.lastname: Cataldi
authors.forename: Fabiana
authors.initials: F
authors.lastname: Bigi
mesh_terms: D000942:Antigens, Bacterial / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics*; D001665:Binding Sites; D024202:Electrophoretic Mobility Shift Assay; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D006801:Humans; D009169:Mycobacterium tuberculosis / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity; D009875:Operator Regions, Genetic; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012097:Repressor Proteins / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D014158:Transcription, Genetic; D014774:Virulence / Q000235:genetics
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D012097:Repressor Proteins; C443482:mce2 protein, Mycobacterium tuberculosis