Alternating dynamics of oriC, SMC and MksBEF in segregation of Pseudomonas aeruginosa chromosome

AbstractCondensins are essential for global chromosome organization in diverse bacteria. Atypically, Pseudomonas aeruginosa encodes condensins from two superfamilies, SMC-ScpAB and MksBEF. We report that the two proteins play specialized roles in chromosome packing and segregation and are synthetically lethal with ParB. Inactivation of SMC or MksB asymmetrically affected global chromosome layout, its timing of segregation and sometimes triggered a chromosomal inversion. Localization pattern was also unique to each protein. SMC clusters colocalized with oriC throughout cell cycle except shortly after origin duplication, whereas MksB clusters emerged at cell quarters shortly prior to oriC duplication and stayed there even after cell division. Relocation of the proteins was abrupt and coordinated with oriC dynamic. These data reveal that the two condensins asymmetrically play dual roles in chromosome maintenance by organizing it and mediating its segregation. Furthermore, the choreography of condensins and oriC relocations suggest an elegant mechanism for the birth and maturation of chromosomes.ImportanceMechanisms that define the chromosome as a structural entity remain unknown. A key element in this process are condensins, which globally organize chromosomes and contribute to their segregation. This study characterized condensin and chromosome dynamics in Pseudomonas aeruginosa, which harbors condensins from two major protein superfamilies, SMC and MksBEF. The study revealed that both proteins asymmetrically play a dual role in chromosome maintenance by spatially organizing the chromosomes and guiding their segregation but can substitute for each other in some activities. The timing of chromosome, SMC and MksBEF relocation was highly ordered and interdependent revealing causative relationships in the process. Moreover, MksBEF was found to produce clusters at the site of chromosome replication that survived cell division and remained in place until chromosome replication was complete. Overall, these data delineate the functions of condensins from the SMC MksBEF superfamilies, reveal the existence of a chromosome organizing center and suggest a mechanism that might explain the biogenesis of chromosomes.

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Alternating Dynamics of oriC, SMC, and MksBEF in Segregation of Pseudomonas aeruginosa Chromosome

mSphere ◽

10.1128/msphere.00238-20 ◽

2020 ◽

Vol 5 (5) ◽

Author(s):

Hang Zhao ◽

Bijit K. Bhowmik ◽

Zoya M. Petrushenko ◽

Valentin V. Rybenkov

Keyword(s):

Pseudomonas Aeruginosa ◽

Cell Division ◽

Chromosome Replication ◽

Dual Role ◽

Major Protein ◽

Content Type ◽

Chromosome Dynamics ◽

Protein Superfamilies ◽

Organizing Center ◽

Structural Entity

Mechanisms that define the chromosome as a structural entity remain unknown. Key elements in this process are condensins, which globally organize chromosomes and contribute to their segregation. This study characterized condensin and chromosome dynamics in Pseudomonas aeruginosa, which harbors condensins from two major protein superfamilies, SMC and MksBEF. The study revealed that both proteins play a dual role in chromosome maintenance by spatially organizing the chromosomes and guiding their segregation but can substitute for each other in some activities. The timing of chromosome, SMC, and MksBEF relocation was highly ordered and interdependent, revealing causative relationships in the process. Moreover, MksBEF produced clusters at the site of chromosome replication that survived cell division and remained in place until replication was complete. Overall, these data delineate the functions of condensins from the SMC and MksBEF superfamilies, reveal the existence of a chromosome organizing center, and suggest a mechanism that might explain the biogenesis of chromosomes.

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MexAB-OprM Efflux Pump Interaction with the Peptidoglycan of Escherichia coli and Pseudomonas aeruginosa

International Journal of Molecular Sciences ◽

10.3390/ijms22105328 ◽

2021 ◽

Vol 22 (10) ◽

pp. 5328

Author(s):

Miao Ma ◽

Margaux Lustig ◽

Michèle Salem ◽

Dominique Mengin-Lecreulx ◽

Gilles Phan ◽

...

Keyword(s):

Escherichia Coli ◽

Pseudomonas Aeruginosa ◽

Cell Division ◽

Membrane Proteins ◽

Outer Membrane ◽

Efflux Pump ◽

Gram Negative Bacteria ◽

Gram Negative ◽

Active Efflux

One of the major families of membrane proteins found in prokaryote genome corresponds to the transporters. Among them, the resistance-nodulation-cell division (RND) transporters are highly studied, as being responsible for one of the most problematic mechanisms used by bacteria to resist to antibiotics, i.e., the active efflux of drugs. In Gram-negative bacteria, these proteins are inserted in the inner membrane and form a tripartite assembly with an outer membrane factor and a periplasmic linker in order to cross the two membranes to expulse molecules outside of the cell. A lot of information has been collected to understand the functional mechanism of these pumps, especially with AcrAB-TolC from Escherichia coli, but one missing piece from all the suggested models is the role of peptidoglycan in the assembly. Here, by pull-down experiments with purified peptidoglycans, we precise the MexAB-OprM interaction with the peptidoglycan from Escherichia coli and Pseudomonas aeruginosa, highlighting a role of the peptidoglycan in stabilizing the MexA-OprM complex and also differences between the two Gram-negative bacteria peptidoglycans.

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The dual roles of AlgG in C-5-epimerization and secretion of alginate polymers in Pseudomonas aeruginosa

Molecular Microbiology ◽

10.1046/j.1365-2958.2003.03361.x ◽

2003 ◽

Vol 47 (4) ◽

pp. 1123-1133 ◽

Cited By ~ 47

Author(s):

Sumita Jain ◽

Michael J. Franklin ◽

Helga Ertesvåg ◽

Svein Valla ◽

Dennis E. Ohman

Keyword(s):

Pseudomonas Aeruginosa ◽

Dual Roles

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c-di-GMP heterogeneity is generated by the chemotaxis machinery to regulate flagellar motility

eLife ◽

10.7554/elife.01402 ◽

2013 ◽

Vol 2 ◽

Cited By ~ 68

Author(s):

Bridget R Kulasekara ◽

Cassandra Kamischke ◽

Hemantha D Kulasekara ◽

Matthias Christen ◽

Paul A Wiggins ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Cell Division ◽

Histidine Kinase ◽

Molecular Basis ◽

Individual Cell ◽

Cell Heterogeneity ◽

Flagellar Motility ◽

Bacterial Populations ◽

Phosphorylation State ◽

Asymmetric Partitioning

Individual cell heterogeneity is commonly observed within populations, although its molecular basis is largely unknown. Previously, using FRET-based microscopy, we observed heterogeneity in cellular c-di-GMP levels. In this study, we show that c-di-GMP heterogeneity in Pseudomonas aeruginosa is promoted by a specific phosphodiesterase partitioned after cell division. We found that subcellular localization and reduction of c-di-GMP levels by this phosphodiesterase is dependent on the histidine kinase component of the chemotaxis machinery, CheA, and its phosphorylation state. Therefore, individual cell heterogeneity in c-di-GMP concentrations is regulated by the activity and the asymmetrical inheritance of the chemotaxis organelle after cell division. c-di-GMP heterogeneity results in a diversity of motility behaviors. The generation of diverse intracellular concentrations of c-di-GMP by asymmetric partitioning is likely important to the success and survival of bacterial populations within the environment by allowing a variety of motility behaviors.

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