scholarly journals Induction of the cydAB Operon Encoding the bd Quinol Oxidase Under Respiration-Inhibitory Conditions by the Major cAMP Receptor Protein MSMEG_6189 in Mycobacterium smegmatis

2020 ◽  
Vol 11 ◽  
Author(s):  
Eon-Min Ko ◽  
Jeong-Il Oh

The respiratory electron transport chain (ETC) of Mycobacterium smegmatis is terminated with two terminal oxidases, the aa3 cytochrome c oxidase and the cytochrome bd quinol oxidase. The bd quinol oxidase with a higher binding affinity for O2 than the aa3 oxidase is known to play an important role in aerobic respiration under oxygen-limiting conditions. Using relevant crp1 (MSMEG_6189) and crp2 (MSMEG_0539) mutant strains of M. smegmatis, we demonstrated that Crp1 plays a predominant role in induction of the cydAB operon under ETC-inhibitory conditions. Two Crp-binding sequences were identified upstream of the cydA gene, both of which are necessary for induction of cydAB expression under ETC-inhibitory conditions. The intracellular level of cAMP in M. smegmatis was found to be increased under ETC-inhibitory conditions. The crp2 gene was found to be negatively regulated by Crp1 and Crp2, which appears to lead to significantly low cellular abundance of Crp2 relative to Crp1 in M. smegmatis. Our RNA sequencing analyses suggest that in addition to the SigF partner switching system, Crp1 is involved in induction of gene expression in M. smegmatis exposed to ETC-inhibitory conditions.

1983 ◽  
Vol 258 (11) ◽  
pp. 6979-6983 ◽  
Author(s):  
R Rangel-Aldao ◽  
G Tovar ◽  
M Ledezma de Ruiz

1999 ◽  
Vol 337 (3) ◽  
pp. 415-423 ◽  
Author(s):  
Emma C. LAW ◽  
Nigel J. SAVERY ◽  
Stephen J. W. BUSBY

The Escherichia coli cAMP receptor protein (CRP) is a factor that activates transcription at over 100 target promoters. At Class I CRP-dependent promoters, CRP binds immediately upstream of RNA polymerase and activates transcription by making direct contacts with the C-terminal domain of the RNA polymerase α subunit (αCTD). Since αCTD is also known to interact with DNA sequence elements (known as UP elements), we have constructed a series of semi-synthetic Class I CRP-dependent promoters, carrying both a consensus DNA-binding site for CRP and a UP element at different positions. We previously showed that, at these promoters, the CRP–αCTD interaction and the CRP–UP element interaction contribute independently and additively to transcription initiation. In this study, we show that the two halves of the UP element can function independently, and that, in the presence of the UP element, the best location for the DNA site for CRP is position -69.5. This suggests that, at Class I CRP-dependent promoters where the DNA site for CRP is located at position -61.5, the two αCTDs of RNA polymerase are not optimally positioned. Two experiments to test this hypothesis are presented.


2000 ◽  
Vol 275 (9) ◽  
pp. 6241-6245 ◽  
Author(s):  
Hidehisa Yoshimura ◽  
Toru Hisabori ◽  
Shuichi Yanagisawa ◽  
Masayuki Ohmori

Microbiology ◽  
2006 ◽  
Vol 152 (9) ◽  
pp. 2749-2756 ◽  
Author(s):  
Nisheeth Agarwal ◽  
Tirumalai R. Raghunand ◽  
William R. Bishai

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 CRPM (encoded by the M. tuberculosis gene Rv3676) to the whiB1 5′ untranslated region (5′UTR). β-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 CRPM to a consensus CRP-binding site in the whiB1 5′UTR.


1995 ◽  
Vol 270 (37) ◽  
pp. 21679-21683 ◽  
Author(s):  
Inna Gorshkova ◽  
Julie L. Moore ◽  
Keith H. McKenney ◽  
Frederick P. Schwarz

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