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HemR is a OmpR/PhoB-like response regulator from Leptospira, which simultaneously effects transcriptional activation and repression of key heme metabolism genes.
MedLine Citation:
PMID:  25145397     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Several Leptospira species cause leptospirosis, the most extended zoonosis worldwide. In bacteria, two component systems constitute key signaling pathways, some of which are involved in pathogenesis. The physiologic roles of two component systems in Leptospira are largely unknown, despite identifying several dozens within their genomes. Biochemical confirmation of an operative phosphorelaying two component system has been obtained so far only for the Hklep/Rrlep pair. It is known that hklep/rrlep knock-out strains of L. biflexa result in heme auxotrophy, although their de novo biosynthesis machinery remains fully functional. Heme is essential for Leptospira, but information about Hklep/Rrlep effector function(s) and target(s) is still lacking. We are now reporting a thorough molecular characterization of this system, which we rename HemK/HemR. The DNA HemR-binding motif was determined, and found within the genomes of saprophyte and pathogenic Leptospira. In this way, putative HemR-regulated genes were pinpointed, including heme catabolism-related (hmuO - heme oxygenase) and biosynthesis-related (the hemA/C/D/B/L/E/N/G operon). Specific HemR binding to these two promoters was quantified, and a dual function was observed in vivo, inversely repressing the hmuO, while activating the hemA operon transcription. The crystal structure of HemR receiver domain was determined, leading to a mechanistic model for its dual regulatory role.
Authors:
Natalia R Morero; Horacio Botti; Kazuhiro R Nitta; Federico Carrión; Gonzalo Obal; Mathieu Picardeau; Alejandro Buschiazzo
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2014-8-22
Journal Detail:
Title:  Molecular microbiology     Volume:  -     ISSN:  1365-2958     ISO Abbreviation:  Mol. Microbiol.     Publication Date:  2014 Aug 
Date Detail:
Created Date:  2014-8-22     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8712028     Medline TA:  Mol Microbiol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
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This article is protected by copyright. All rights reserved.
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