Mce2R from Mycobacterium tuberculosis represses the expression of the mce2 operon.
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.
Santangelo
María de la Paz
Mde L
Institute of Biotechnology, CICVyA-INTA Castelar, N. Repetto and Los Reseros Hurlingham, Argentina.
Blanco
Federico
F
Campos
Eleonora
E
Soria
Marcelo
M
Bianco
María Verónica
MV
Klepp
Laura
L
Alito
Alicia
A
Zabal
Osvaldo
O
Cataldi
Angel
A
Bigi
Fabiana
F
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
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D012097:Repressor Proteins; C443482:mce2 protein, Mycobacterium tuberculosis