The nucleoid-associated proteins H-NS and FIS modulate the DNA supercoiling response of the pel genes, the major virulence factors in the plant pathogen bacterium Dickeya dadantii
Open Access
- 24 January 2012
- journal article
- research article
- Published by Oxford University Press (OUP) in Nucleic Acids Research
- Vol. 40 (10), 4306-4319
- https://doi.org/10.1093/nar/gks014
Abstract
Dickeya dadantii is a pathogen infecting a wide range of plant species. Soft rot, the visible symptom, is mainly due to the production of pectate lyases (Pels) that can destroy the plant cell walls. Previously we found that the pel gene expression is modulated by H-NS and FIS, two nucleoid-associated proteins (NAPs) modulating the DNA topology. Here, we show that relaxation of the DNA in growing D. dadantii cells decreases the expression of pel genes. Deletion of fis aggravates, whereas that of hns alleviates the negative impact of DNA relaxation on pel expression. We further show that H-NS and FIS directly bind the pelE promoter and that the response of D. dadantii pel genes to stresses that induce DNA relaxation is modulated, although to different extents, by H-NS and FIS. We infer that FIS acts as a repressor buffering the negative impact of DNA relaxation on pel gene transcription, whereas H-NS fine-tunes the response of virulence genes precluding their expression under suboptimal conditions of supercoiling. This novel dependence of H-NS effect on DNA topology expands our understanding of the role of NAPs in regulating the global bacterial gene expression and bacterial pathogenicity.Keywords
This publication has 75 references indexed in Scilit:
- A multifactor regulatory circuit involving H-NS, VirF and an antisense RNA modulates transcription of the virulence gene icsA of Shigella flexneriNucleic Acids Research, 2011
- Toward a Quantitative Modeling of the Synthesis of the Pectate Lyases, Essential Virulence Factors in Dickeya dadantiiPublished by Elsevier BV ,2010
- A divalent switch drives H-NS/DNA-binding conformations between stiffening and bridging modesGenes & Development, 2010
- Bacterial DNA topology and infectious diseaseNucleic Acids Research, 2008
- H-NS family members function coordinately in an opportunistic pathogenProceedings of the National Academy of Sciences of the United States of America, 2008
- Functional Characterization of the Escherichia coli Fis–DNA Binding SequenceJournal of Molecular Biology, 2008
- High-affinity DNA binding sites for H-NS provide a molecular basis for selective silencing within proteobacterial genomesNucleic Acids Research, 2007
- A common topology for bacterial and eukaryotic transcription initiation?EMBO Reports, 2007
- Homeostatic regulation of supercoiling sensitivity coordinates transcription of the bacterial genomeEMBO Reports, 2006
- Relative expression software tool (REST(C)) for group-wise comparison and statistical analysis of relative expression results in real-time PCRNucleic Acids Research, 2002