Temporal control of Dickeya dadantii main virulence gene expression by growth phase-dependent alteration of regulatory nucleoprotein complexes

Structural differentiation of bacterial chromatin depends on cooperative binding of abundant nucleoid-associated proteins at numerous genomic DNA sites and stabilization of distinct long-range nucleoprotein structures. Histone-like nucleoid-structuring protein (H-NS) is an abundant DNA-bridging, nucleoid-associated protein that binds to an AT-rich conserved DNA sequence motif and regulates both the shape and the genetic expression of the bacterial chromosome. Although there is ample evidence that the mode of H-NS binding depends on environmental conditions, the role of the spatial organization of H-NS-binding sequences in the assembly of long-range nucleoprotein structures remains unknown. In this study, by using high-resolution atomic force microscopy combined with biochemical assays, we explored the formation of H-NS nucleoprotein complexes on circular DNA molecules having different arrangements of identical sequences containing high-affinity H-NS-binding sites. We provide the first experimental evidence that variable sequence arrangements result in various three-dimensional nucleoprotein structures that differ in their shape and the capacity to constrain supercoils and compact the DNA. We believe that the DNA sequence-directed versatile assembly of periodic higher-order structures reveals a general organizational principle that can be exploited for knowledge-based design of long-range nucleoprotein complexes and purposeful manipulation of the bacterial chromatin architecture.

show abstract

“…The product was then loaded onto a sequencing gel. Sequencing reactions were performed as previously described (56). …”

Section: Methodsmentioning

confidence: 99%

Spatial organization of DNA sequences directs the assembly of bacterial chromatin by a nucleoid-associated protein

Japaridze

Renevey

Sobetzko

et al. 2017

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

show abstract

“…Dickeya dadantii was transformed with various pProbe plasmids and was cultured in 96‐well plates as described previously . Real‐time mRNA levels were computed from fluorescence data using the model described in .…”

Section: Methodsmentioning

confidence: 99%

“…This absence of expression is probably linked to the absence of CRP1binding site in the hybrid regulatory region. Indeed, we demonstrated that CRP1 is necessary for expression of a pelD-like promoter [24]. We next measured real-time mRNA levels produced by the pel promoter constructs as described above.…”

Section: Structural Modifications Of the Peld And Pele Regulatory Regmentioning

confidence: 99%

See 1 more Smart Citation

Transcriptional start site turnover in the evolution of bacterial paralogous genes – the pelE‐pelD virulence genes in Dickeya

et al. 2016

Self Cite

View full text Add to dashboard Cite

After a gene duplication event, the resulting paralogous genes frequently acquire distinct expression profiles, roles, and/or functions but the underlying mechanisms are poorly understood. While transcription start site (TSS) turnover, i.e., the repositioning of the TSS during evolution, is widespread in eukaryotes, it is less documented in bacteria. Using pelD and pelE, two closely related paralogous genes encoding key virulence factors in Dickeya, a gamma proteobacterial genus of phytopathogens, we show that pelE has been selected as an initiator of bacterial aggression, while pelD acts at a later stage, thanks to modifications in the transcriptional regulation of these two genes. This expression change is linked to a few mutations that caused a shift in the position of the pelETSS and the rapid divergence in the regulation of these genes after their duplication. Genomic surveys detected additional examples of putative turnovers in other bacteria. This first report of TSS shifting in bacteria suggests that this mechanism could play a major role in paralogous genes fixation in prokaryotes.

show abstract

“…Fis plays a pivotal role in the expression of the main virulence genes by activating the factors required at the early stages of infection (flagella and detoxification of bactericidal compounds) while repressing the pel genes ( Fig. 3) Duprey et al, 2014;Duprey et al, 2016a). As bacteria multiply in planta, the cellular concentration of Fis progressively decreases and the repression of pel genes is relieved (Fig.…”

Section: Dickeya Dadantiimentioning

confidence: 99%

Plant–phytopathogen interactions: bacterial responses to environmental and plant stimuli

Léonard

Hommais

Nasser

et al. 2017

Environmental Microbiology

Self Cite

View full text Add to dashboard Cite

Summary Plant pathogenic bacteria attack numerous agricultural crops, causing devastating effects on plant productivity and yield. They survive in diverse environments, both in plants, as pathogens, and also outside their hosts as saprophytes. Hence, they are confronted with numerous changing environmental parameters. During infection, plant pathogens have to deal with stressful conditions, such as acidic, oxidative and osmotic stresses; anaerobiosis; plant defenses; and contact with antimicrobial compounds. These adverse conditions can reduce bacterial survival and compromise disease initiation and propagation. Successful bacterial plant pathogens must detect potential hosts and also coordinate their possibly conflicting programs for survival and virulence. Consequently, these bacteria have a strong and finely tuned capacity for sensing and responding to environmental and plant stimuli. This review summarizes our current knowledge of the signals and genetic circuits that affect survival and virulence factor expression in three important and well‐studied plant pathogenic bacteria with wide host ranges and the capacity for long‐term environmental survival. These are: Ralstonia solanacerarum, a vascular pathogen that causes wilt disease; Agrobacterium tumefaciens, a biotrophic tumorigenic pathogen responsible for crown gall disease and Dickeya, a brute force apoplastic pathogen responsible for soft‐rot disease.

show abstract

Temporal control of Dickeya dadantii main virulence gene expression by growth phase-dependent alteration of regulatory nucleoprotein complexes

Cited by 16 publications

References 58 publications

Spatial organization of DNA sequences directs the assembly of bacterial chromatin by a nucleoid-associated protein

Spatial organization of DNA sequences directs the assembly of bacterial chromatin by a nucleoid-associated protein

Transcriptional start site turnover in the evolution of bacterial paralogous genes – the pelE‐pelD virulence genes in Dickeya

Plant–phytopathogen interactions: bacterial responses to environmental and plant stimuli

Contact Info

Product

Resources

About