Document Detail

The two-component system ChrSA is crucial for heme tolerance and interferes with HrrSA in heme-dependent gene regulation in Corynebacterium glutamicum.
MedLine Citation:
PMID:  23038807     Owner:  NLM     Status:  Publisher    
We recently showed that the two-component system (TCS) HrrSA plays a central role in the control of heme homeostasis in the Gram-positive soil bacterium Corynebacterium glutamicum. Here, we characterized the function of another TCS of this organism, ChrSA, which exhibits significant sequence similarity to HrrSA, and provide evidence for cross-regulation of the two systems. In this study, ChrSA was shown to be crucial for heme resistance of C. glutamicum by activation of the putative heme-detoxifying ABC-transporter HrtBA in the presence of heme. Deletion of either hrtBA or chrSA resulted in a strongly increased sensitivity towards heme. DNA microarray analysis and gel retardation assays with the purified response regulator ChrA revealed that phosphorylated ChrA acts as an activator of hrtBA in the presence of heme. The heme oxygenase gene, hmuO, showed a decreased mRNA level in a chrSA deletion mutant but no significant binding of ChrA to the hmuO promoter was observed in vitro. In contrast, activation from P(hmuO) fused to eyfp was almost abolished in a hrrSA mutant indicating that HrrSA is the dominant system for heme-dependent activation of hmuO in C. glutamicum. Remarkably, ChrA was also shown to bind to the hrrA promoter and to repress transcription of the paralogous response regulator, whereas chrSA itself seemed to be repressed by HrrA. These data suggest a close interplay of HrrSA and ChrSA at the level of transcription and emphasize ChrSA as a second TCS involved in heme-dependent gene regulation in C. glutamicum, besides HrrSA.
Antonia Heyer; Cornelia Gätgens; Eva Hentschel; Jörn Kalinowski; Michael Bott; Julia Frunzke
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-10-4
Journal Detail:
Title:  Microbiology (Reading, England)     Volume:  -     ISSN:  1465-2080     ISO Abbreviation:  Microbiology (Reading, Engl.)     Publication Date:  2012 Oct 
Date Detail:
Created Date:  2012-10-5     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9430468     Medline TA:  Microbiology     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Forschungszentrum Julich;
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