TY - JOUR
T1 - 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
AU - Elvers, KT
AU - Turner, Susan
AU - Wainwright, LM
AU - Marsden, G
AU - Hinds, J
AU - Cole, Jeffrey
AU - Poole, RK
AU - Penn, Charles
AU - Park, SF
PY - 2005/8/1
Y1 - 2005/8/1
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=22644447132&partnerID=8YFLogxK
U2 - 10.1111/j.1365-2958.2005.04723.x
DO - 10.1111/j.1365-2958.2005.04723.x
M3 - Article
C2 - 16045618
SN - 0950-382X
VL - 57
SP - 735
EP - 750
JO - Molecular Microbiology
JF - Molecular Microbiology
IS - 3
ER -