PMID:16045618

Citation	Elvers, KT, Turner, SM, Wainwright, LM, Marsden, G, Hinds, J, Cole, JA, Poole, RK, Penn, CW and Park, SF (2005) NssR, a member of the Crp-Fnr superfamily from Campylobacter jejuni, regulates a nitrosative stress-responsive regulon that includes both a single-domain and a truncated haemoglobin. Mol. Microbiol. 57:735-50
Abstract	Consistent with its role as a nitric oxide (NO)-detoxifying globin in Campylobacter jejuni, Cgb (Campylobacter globin) expression is strongly and specifically induced following exposure to nitrosative stress, suggesting a previously unrecognized capacity for NO-related stress sensing in this food-borne pathogen. In this study, Fur and PerR have been eliminated as major regulators of cgb, and NssR (Cj0466), a member of the Crp-Fnr superfamily, has been identified as the major positive regulatory factor that controls nitrosative stress-responsive expression of this gene. Accordingly, disruption of nssR resulted in the abolition of inducible cgb expression, which was restored by a complementing chromosomal insertion of the wild-type gene with its indigenous promoter at a second location. The NssR-deficient mutant was more sensitive to NO-related stress than a cgb mutant and this phenotype most likely arises from the failure of these cells to induce other NO-responsive components in addition to Cgb. Indeed, analysis of global gene expression, by microarray and confirmatory real-time polymerase chain reaction (PCR) in the wild type and nssR mutant, not only confirmed the dependence of inducible cgb expression on NssR, but also revealed for the first time a novel NssR-dependent nitrosative stress-responsive regulon. This regulon of at least four genes includes Cj0465c, a truncated globin. Consistent with NssR being a Crp-Fnr superfamily member, an Fnr-like binding sequence (TTAAC-N(4)-GTTAA) was found upstream of each gene at locations -40.5 to -42.5 relative to the centre of the binding sites and the transcription start point. Site-directed mutagenesis confirmed that this cis-acting motif mediates the nitrosative stress-inducible expression of cgb.
Links	PubMed Online version:10.1111/j.1365-2958.2005.04723.x
Keywords	Bacterial Proteins/genetics; Bacterial Proteins/metabolism; Base Sequence; Campylobacter jejuni/genetics; Campylobacter jejuni/metabolism; Campylobacter jejuni/physiology; Cyclic AMP Receptor Protein; Escherichia coli Proteins; Gene Expression Regulation, Bacterial; Heat-Shock Response; Hemoglobins/chemistry; Hemoglobins/genetics; Hemoglobins/metabolism; Iron-Sulfur Proteins; Molecular Sequence Data; Mutation; Oligonucleotide Array Sequence Analysis; Oxidative Stress; Promoter Regions, Genetic; Reactive Nitrogen Species/metabolism; Receptors, Cell Surface; Regulon/genetics; Regulon/physiology; Transcription Factors; Transcription, Genetic; Truncated Hemoglobins
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
OCHAN:C0A1E1		GO:1900079: regulation of arginine biosynthetic process	ECO:0000315:		P		Figure 1: with NssR being a Crp-Fnr superfamily member, an Fnr-like binding sequence (TTAAC-N(4)-GTTAA) was found upstream of each gene at locations -40.5 to -42.5 relative to the centre of the binding sites and the transcription start point.	complete CACAO 10727

References

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