[The role of transcriptional regulators in the control of gene expression in prokaryotes based on Pseudomonas aeruginosa model bacterium].

Bacteria from Pseudomonas aeruginosa species are often found in environments such as water or soil, but are also known to be opportunistic pathogens of humans and animals. Characteristic feature of these bacteria is their high ability to survive in very different ecological niches. Such capability of adaptation to changing conditions is derived from the extended regulatory networks and the use of a rich repertoire of genome-encoded proteins, pathways and adaptive mechanisms.

Robust ParB Binding to Half- Sites in -A Mechanism for Retaining ParB on the Nucleoid?

Chromosome segregation in is assisted by the tripartite ParAB- system, composed of an ATPase (ParA), a DNA-binding protein (ParB) and its target sequence(s). ParB forms a nucleoprotein complex around four s () that overlaps and facilitates relocation of newly synthesized ori domains inside the cells by ParA. Remarkably, ParB of also binds to numerous heptanucleotides (half-s) scattered in the genome.

Diverse Partners of the Partitioning ParB Protein in Pseudomonas aeruginosa.

In the majority of bacterial species, the tripartite ParAB- system, composed of an ATPase (ParA), a DNA-binding protein (ParB), and its target sequence(s), assists in the chromosome partitioning. ParB forms large nucleoprotein complexes at (s), located in the vicinity of origin of chromosomal replication (), which after replication are subsequently positioned by ParA in cell poles. Remarkably, ParA and ParB participate not only in the chromosome segregation but through interactions with various cellular partners they are also involved in other cell cycle-related processes, in a species-specific manner.

Functional Characterization of TetR-like Transcriptional Regulator PA3973 from .

Pseudomonas aeruginosa, a human opportunistic pathogen, is a common cause of nosocomial infections. Its ability to survive under different conditions relies on a complex regulatory network engaging transcriptional regulators controlling metabolic pathways and capabilities to efficiently use the available resources. P.

The Lrp/AsnC-Type Regulator PA2577 Controls the EamA-like Transporter Gene in .

The regulatory network of gene expression in , an opportunistic human pathogen, is very complex. In the PAO1 reference strain, about 10% of genes encode transcriptional regulators, many of which have undefined regulons and unknown functions. The aim of this study is the characterization of PA2577 protein, a representative of the Lrp/AsnC family of transcriptional regulators.

The LysR-Type Transcriptional Regulator BsrA (PA2121) Controls Vital Metabolic Pathways in .

Pseudomonas aeruginosa, a facultative human pathogen causing nosocomial infections, has complex regulatory systems involving many transcriptional regulators. LTTR (LysR-Type Transcriptional Regulator) family proteins are involved in the regulation of various processes, including stress responses, motility, virulence, and amino acid metabolism. The aim of this study was to characterize the LysR-type protein BsrA (PA2121), previously described as a negative regulator of biofilm formation in P.

The AraC-Type Transcriptional Regulator GliR (PA3027) Activates Genes of Glycerolipid Metabolism in .

encodes a large set of transcriptional regulators (TRs) that modulate and manage cellular metabolism to survive in variable environmental conditions including that of the human body. The AraC family regulators are an abundant group of TRs in bacteria, mostly acting as gene expression activators, controlling diverse cellular functions (e.g.

The MarR-Type Regulator PA3458 Is Involved in Osmoadaptation Control in .

is a facultative human pathogen, causing acute and chronic infections that are especially dangerous for immunocompromised patients. The eradication of is difficult due to its intrinsic antibiotic resistance mechanisms, high adaptability, and genetic plasticity. The bacterium possesses multilevel regulatory systems engaging a huge repertoire of transcriptional regulators (TRs).

Rules and Exceptions: The Role of Chromosomal ParB in DNA Segregation and Other Cellular Processes.

The segregation of newly replicated chromosomes in bacterial cells is a highly coordinated spatiotemporal process. In the majority of bacterial species, a tripartite ParAB- system, composed of an ATPase (ParA), a DNA-binding protein (ParB), and its target(s) sequence(s), facilitates the initial steps of chromosome partitioning. ParB nucleates around (s) located in the vicinity of newly replicated s to form large nucleoprotein complexes, which are subsequently relocated by ParA to distal cellular compartments.

Genome sequence of Pseudomonas aeruginosa PAO1161, a PAO1 derivative with the ICEPae1161 integrative and conjugative element.

Background: Pseudomonas aeruginosa is a cause of nosocomial infections, especially in patients with cystic fibrosis and burn wounds. PAO1 strain and its derivatives are widely used to study the biology of this bacterium, however recent studies demonstrated differences in the genomes and phenotypes of derivatives from different laboratories.

Results: Here we report the genome sequence of P.

Interaction of ArmZ with the DNA-binding domain of MexZ induces expression of multidrug efflux pump genes and antimicrobial resistance in .

Multidrug efflux pumps play an important role in antibiotic resistance in bacteria. In , MexXY pump provides intrinsic resistance to many antimicrobials, including aminoglycosides. The expression of operon is negatively regulated by MexZ repressor.

Pseudomonas aeruginosa partitioning protein ParB acts as a nucleoid-associated protein binding to multiple copies of a parS-related motif.

ParA and ParB homologs are involved in accurate chromosome segregation in bacteria. ParBs participate in the separation of ori domains by binding to parS palindromes, mainly localized close to oriC. In Pseudomonas aeruginosa neither ParB deficiency nor modification of all 10 parSs is lethal.

Increased ParB level affects expression of stress response, adaptation and virulence operons and potentiates repression of promoters adjacent to the high affinity binding sites parS3 and parS4 in Pseudomonas aeruginosa.

Similarly to its homologs in other bacteria, Pseudomonas aeruginosa partitioning protein ParB facilitates segregation of newly replicated chromosomes. Lack of ParB is not lethal but results in increased frequency of anucleate cells production, longer division time, cell elongation, altered colony morphology and defective swarming and swimming motility. Unlike in other bacteria, inactivation of parB leads to major changes of the transcriptome, suggesting that, directly or indirectly, ParB plays a role in regulation of gene expression in this organism.

Concerted action of NIC relaxase and auxiliary protein MobC in RA3 plasmid conjugation.

Conjugative transfer of the broad-host-range RA3 plasmid, the archetype of the IncU group, relies on the relaxase NIC that belongs to the as yet uncharacterized MOBP4 subfamily. NIC contains the signature motifs of HUH relaxases involved in Tyr nucleophilic attack. However, it differs in the residue involved in His activation for cation coordination and was shown here to have altered divalent cation requirements.

Convenient broad-host-range unstable vectors for studying stabilization cassettes in diverse bacteria.

Background: Low-copy-number vectors of potential wide application in biotechnology need to encode stabilization modules ensuring their stable inheritance. The efficiency of stabilization may vary depending on the plasmid host so a thorough analysis of stabilization functions is required before use.

Results: To facilitate such analysis highly unstable, mobilizable, broad-host-range (BHR) vectors based on RK2 replicon were constructed.

A single parS sequence from the cluster of four sites closest to oriC is necessary and sufficient for proper chromosome segregation in Pseudomonas aeruginosa.

Among the mechanisms that control chromosome segregation in bacteria are highly-conserved partitioning systems comprising three components: ParA protein (a deviant Walker-type ATPase), ParB protein (a DNA-binding element) and multiple cis-acting palindromic centromere-like sequences, designated parS. Ten putative parS sites have been identified in the P. aeruginosa PAO1 genome, four localized in close proximity of oriC and six, diverged by more than one nucleotide from a perfect palindromic sequence, dispersed along the chromosome.

Dissection of the region of Pseudomonas aeruginosa ParA that is important for dimerization and interactions with its partner ParB.

Pseudomonas aeruginosa ParA belongs to a large subfamily of Walker-type ATPases acting as partitioning proteins in bacteria. ParA has the ability to both self-associate and interact with its partner ParB. Analysis of the deletion mutants defined the part of the protein involved in dimerization and interactions with ParB.

Transcriptional profiling of ParA and ParB mutants in actively dividing cells of an opportunistic human pathogen Pseudomonas aeruginosa.

Accurate chromosome segregation to progeny cells is a fundamental process ensuring proper inheritance of genetic material. In bacteria with simple cell cycle, chromosome segregation follows replication initiation since duplicated oriC domains start segregating to opposite halves of the cell soon after they are made. ParA and ParB proteins together with specific DNA sequences are parts of the segregation machinery.

Novel broad-host-range vehicles for cloning and shuffling of gene cassettes.

Novel vectors for cloning and shuffling of gene cassettes based on minireplicon of broad-host-range RA3 plasmid from IncU incompatibility group were constructed. A series of minireplicon variants were prepared with copy number ranging from low (1-2 copies per chromosome), medium (10-15 copies per chromosome) to high copy number (80-90 copies per chromosome). The new cloning vectors are relatively small in size (4.

Deletion of the parA (soj) homologue in Pseudomonas aeruginosa causes ParB instability and affects growth rate, chromosome segregation, and motility.

The parA and parB genes of Pseudomonas aeruginosa are located approximately 8 kb anticlockwise from oriC. ParA is a cytosolic protein present at a level of around 600 molecules per cell in exponential phase, but the level drops about fivefold in stationary phase. Overproduction of full-length ParA or the N-terminal 85 amino acids severely inhibits growth of P.

Bacterial chromosome segregation.

In most bacteria two vital processes of the cell cycle: DNA replication and chromosome segregation overlap temporally. The action of replication machinery in a fixed location in the cell leads to the duplication of oriC regions, their rapid separation to the opposite halves of the cell and the duplicated chromosomes gradually moving to the same locations prior to cell division. Numerous proteins are implicated in co-replicational DNA segregation and they will be characterized in this review.

ParB of Pseudomonas aeruginosa: interactions with its partner ParA and its target parS and specific effects on bacterial growth.

The par genes of Pseudomonas aeruginosa have been studied to increase the understanding of their mechanism of action and role in the bacterial cell. Key properties of the ParB protein have been identified and are associated with different parts of the protein. The ParB- ParB interaction domain was mapped in vivo and in vitro to the C-terminal 56 amino acids (aa); 7 aa at the C terminus play an important role.

Characterization of the replicator region of megaplasmid pTAV3 of Paracoccus versutus and search for plasmid-encoded traits.

The replicon of the pTAV3 megaplasmid (approx. 400 kb) of Paracoccus versutus has been localized to a 4center dot3 kb EcoRI restriction fragment and its entire nucleotide sequence determined. The G+C content of the entire sequence is 66 mol%, which is within the range (62-66 mol%) previously determined for P.