Regulation of the expression of whiB1 in Mycobacterium tuberculosis: role of cAMP receptor protein.
The wbl (whiB-like) genes encode putative transcription factors unique to actinomycetes. This study characterized the promoter element of one of the seven wbl genes of Mycobacterium tuberculosis, whiB1 (Rv3219c). The results reveal that whiB1 is transcribed by a class I-type cAMP receptor protein (CRP)-dependent promoter, harbouring a CRP-binding site positioned at -58.5 with respect to its transcription start point. In vivo promoter activity analysis and electrophoretic mobility shift assays suggest that the expression of whiB1 is indeed regulated by cAMP-dependent binding of CRP(M) (encoded by the M. tuberculosis gene Rv3676) to the whiB1 5' untranslated region (5'UTR). beta-Galactosidase gene fusion analysis revealed induction of the whiB1 promoter in M. tuberculosis on addition of exogenous dibutyric cAMP (a diffusible cAMP analogue) only when an intact CRP-binding site was present. These results indicate that M. tuberculosis whiB1 transcription is regulated in part by cAMP levels via direct binding of cAMP-activated CRP(M) to a consensus CRP-binding site in the whiB1 5'UTR.
Agarwal
Nisheeth
N
Department of Medicine, Johns Hopkins University, CRB2, Rm 1.08, 1550 Orleans Street, Baltimore, MD 21231-1044, USA.
Raghunand
Tirumalai R
TR
Department of Medicine, Johns Hopkins University, CRB2, Rm 1.08, 1550 Orleans Street, Baltimore, MD 21231-1044, USA.
Bishai
William R
WR
Department of Medicine, Johns Hopkins University, CRB2, Rm 1.08, 1550 Orleans Street, Baltimore, MD 21231-1044, USA.
D020121:5' Untranslated Regions; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D001665:Binding Sites; D003994:Bucladesine / Q000494:pharmacology; D002373:Cyclic AMP Receptor Protein / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009169:Mycobacterium tuberculosis / Q000235:genetics*; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014158:Transcription, Genetic; D001616:beta-Galactosidase / Q000378:metabolism
D020121:5' Untranslated Regions; D001426:Bacterial Proteins; D002373:Cyclic AMP Receptor Protein; D011993:Recombinant Fusion Proteins; D003994:Bucladesine; D001616:beta-Galactosidase