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Regulatory effects of cAMP receptor protein (CRP) on porin genes and its own gene in Yersinia pestis.

Gao H, Zhang Y, Yang L, Liu X, Guo Z, Tan Y, Han Y, Huang X, Zhou D, Yang R - BMC Microbiol. (2011)

Bottom Line: Y. pestis employs a distinct mechanism indicating that CRP has no regulatory effect on the ompR-envZ operon; however, it stimulates ompC and ompF directly, while repressing ompX.Although the CRP of Y. pestis shows a very high homology to that of E. coli, and the consensus DNA sequence recognized by CRP is shared by the two bacteria, the Y. pestis CRP can recognize the promoters of ompC, F, and X directly rather than that of its own gene, which is different from the relevant regulatory circuit of E. coli.Data presented here indicate a remarkable remodeling of the CRP-mediated regulation of porin genes and of its own one between these two bacteria.

View Article: PubMed Central - HTML - PubMed

Affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, PR China.

ABSTRACT

Background: The cAMP receptor protein (CRP) is a global bacterial regulator that controls many target genes. The CRP-cAMP complex regulates the ompR-envZ operon in E. coli directly, involving both positive and negative regulations of multiple target promoters; further, it controls the production of porins indirectly through its direct action on ompR-envZ. Auto-regulation of CRP has also been established in E. coli. However, the regulation of porin genes and its own gene by CRP remains unclear in Y. pestis.

Results: Y. pestis employs a distinct mechanism indicating that CRP has no regulatory effect on the ompR-envZ operon; however, it stimulates ompC and ompF directly, while repressing ompX. No transcriptional regulatory association between CRP and its own gene can be detected in Y. pestis, which is also in contrast to the fact that CRP acts as both repressor and activator for its own gene in E. coli. It is likely that Y. pestis OmpR and CRP respectively sense different signals (medium osmolarity, and cellular cAMP levels) to regulate porin genes independently.

Conclusion: Although the CRP of Y. pestis shows a very high homology to that of E. coli, and the consensus DNA sequence recognized by CRP is shared by the two bacteria, the Y. pestis CRP can recognize the promoters of ompC, F, and X directly rather than that of its own gene, which is different from the relevant regulatory circuit of E. coli. Data presented here indicate a remarkable remodeling of the CRP-mediated regulation of porin genes and of its own one between these two bacteria.

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Competitive DNase I footprinting analysis. The labeled coding strand of the promoter-proximal DNA fragment of each indicated gene was incubated with His-OmpR, His-CRP or both in the presence of acetyl phosphate and cAMP for DNase I footprinting assay. The thick bold lines indicate the OmpR protected regions, while the thin ones denote CRP footprints. The numbers also indicate the nucleotide positions upstream the transcriptional start sites. We also show the amounts of His-OmpR and His-CRP used in each lane.
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Figure 6: Competitive DNase I footprinting analysis. The labeled coding strand of the promoter-proximal DNA fragment of each indicated gene was incubated with His-OmpR, His-CRP or both in the presence of acetyl phosphate and cAMP for DNase I footprinting assay. The thick bold lines indicate the OmpR protected regions, while the thin ones denote CRP footprints. The numbers also indicate the nucleotide positions upstream the transcriptional start sites. We also show the amounts of His-OmpR and His-CRP used in each lane.

Mentions: There was no overlapping of OmpR- and CRP-binding sites for ompX; however, overlapping regions that were 17 and 2 bp in length were observed for ompC and ompF, respectively. We performed further footprinting experiments using the coding strands of the promoter-proximal DNA fragments of ompC, F, and X with different amounts of OmpR and CRP in various reactions (Figure 6). His-CRP protected each promoter region tested in a dose-dependent manner when His-OmpR-P was at the highest amount (20 pmol), and vice versa. Both His-CRP and His-OmpR-P at the highest amounts were able to bind together to each promoter region tested. These results indicated that no competitive binding occurred between them to these target promoters. It was likely that OmpR and CRP sensed different signals to regulate ompC, F, and X in an independent manner.


Regulatory effects of cAMP receptor protein (CRP) on porin genes and its own gene in Yersinia pestis.

Gao H, Zhang Y, Yang L, Liu X, Guo Z, Tan Y, Han Y, Huang X, Zhou D, Yang R - BMC Microbiol. (2011)

Competitive DNase I footprinting analysis. The labeled coding strand of the promoter-proximal DNA fragment of each indicated gene was incubated with His-OmpR, His-CRP or both in the presence of acetyl phosphate and cAMP for DNase I footprinting assay. The thick bold lines indicate the OmpR protected regions, while the thin ones denote CRP footprints. The numbers also indicate the nucleotide positions upstream the transcriptional start sites. We also show the amounts of His-OmpR and His-CRP used in each lane.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3050693&req=5

Figure 6: Competitive DNase I footprinting analysis. The labeled coding strand of the promoter-proximal DNA fragment of each indicated gene was incubated with His-OmpR, His-CRP or both in the presence of acetyl phosphate and cAMP for DNase I footprinting assay. The thick bold lines indicate the OmpR protected regions, while the thin ones denote CRP footprints. The numbers also indicate the nucleotide positions upstream the transcriptional start sites. We also show the amounts of His-OmpR and His-CRP used in each lane.
Mentions: There was no overlapping of OmpR- and CRP-binding sites for ompX; however, overlapping regions that were 17 and 2 bp in length were observed for ompC and ompF, respectively. We performed further footprinting experiments using the coding strands of the promoter-proximal DNA fragments of ompC, F, and X with different amounts of OmpR and CRP in various reactions (Figure 6). His-CRP protected each promoter region tested in a dose-dependent manner when His-OmpR-P was at the highest amount (20 pmol), and vice versa. Both His-CRP and His-OmpR-P at the highest amounts were able to bind together to each promoter region tested. These results indicated that no competitive binding occurred between them to these target promoters. It was likely that OmpR and CRP sensed different signals to regulate ompC, F, and X in an independent manner.

Bottom Line: Y. pestis employs a distinct mechanism indicating that CRP has no regulatory effect on the ompR-envZ operon; however, it stimulates ompC and ompF directly, while repressing ompX.Although the CRP of Y. pestis shows a very high homology to that of E. coli, and the consensus DNA sequence recognized by CRP is shared by the two bacteria, the Y. pestis CRP can recognize the promoters of ompC, F, and X directly rather than that of its own gene, which is different from the relevant regulatory circuit of E. coli.Data presented here indicate a remarkable remodeling of the CRP-mediated regulation of porin genes and of its own one between these two bacteria.

View Article: PubMed Central - HTML - PubMed

Affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, PR China.

ABSTRACT

Background: The cAMP receptor protein (CRP) is a global bacterial regulator that controls many target genes. The CRP-cAMP complex regulates the ompR-envZ operon in E. coli directly, involving both positive and negative regulations of multiple target promoters; further, it controls the production of porins indirectly through its direct action on ompR-envZ. Auto-regulation of CRP has also been established in E. coli. However, the regulation of porin genes and its own gene by CRP remains unclear in Y. pestis.

Results: Y. pestis employs a distinct mechanism indicating that CRP has no regulatory effect on the ompR-envZ operon; however, it stimulates ompC and ompF directly, while repressing ompX. No transcriptional regulatory association between CRP and its own gene can be detected in Y. pestis, which is also in contrast to the fact that CRP acts as both repressor and activator for its own gene in E. coli. It is likely that Y. pestis OmpR and CRP respectively sense different signals (medium osmolarity, and cellular cAMP levels) to regulate porin genes independently.

Conclusion: Although the CRP of Y. pestis shows a very high homology to that of E. coli, and the consensus DNA sequence recognized by CRP is shared by the two bacteria, the Y. pestis CRP can recognize the promoters of ompC, F, and X directly rather than that of its own gene, which is different from the relevant regulatory circuit of E. coli. Data presented here indicate a remarkable remodeling of the CRP-mediated regulation of porin genes and of its own one between these two bacteria.

Show MeSH