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

Kawalek, Adam and Bartosik, Aneta A and Jagura-Burdzy, Grazyna (2023) Robust ParB Binding to Half-parS Sites in Pseudomonas aeruginosa—A Mechanism for Retaining ParB on the Nucleoid? International Journal of Molecular Sciences, 24(15) (12517). ISSN 1422-0067


Official URL: https://www.mdpi.com/1422-0067/24/15/12517


Chromosome segregation in Pseudomonas aeruginosa is assisted by the tripartite ParAB–parS system, composed of an ATPase (ParA), a DNA-binding protein (ParB) and its target parS sequence(s). ParB forms a nucleoprotein complex around four parSs (parS1–parS4) that overlaps oriC and facilitates relocation of newly synthesized ori domains inside the cells by ParA. Remarkably, ParB of P. aeruginosa also binds to numerous heptanucleotides (half-parSs) scattered in the genome. Here, using chromatin immunoprecipitation-sequencing (ChIP-seq), we analyzed patterns of ParB genome occupancy in cells growing under conditions of coupling or uncoupling between replication and cell division processes. Interestingly, a dissipation of ParB–parS complexes and a shift of ParB to half-parSs were observed during the transition from the exponential to stationary phase of growth on rich medium, suggesting the role of half-parSs in retaining ParB on the nucleoid within non-dividing P. aeruginosa cells. The ChIP-seq analysis of strains expressing ParB variants unable to dislocate from parSs showed that the ParB spreading ability is not required for ParB binding to half-parSs. Finally, a P. aeruginosa strain with mutated 25 half-parSs of the highest affinity towards ParB was constructed and analyzed. It showed altered ParB coverage of the oriC region and moderate changes in gene expression. Overall, this study characterizes a novel aspect of conserved bacterial chromosome segregation machinery.

Item Type:Article
Uncontrolled Keywords:Pseudomonas aeruginosa; chromosome segregation; partitioning proteins; ParB distribution; half-parSs
Subjects:Q Science > Q Science (General)
Q Science > QR Microbiology
Divisions:Department of Microbial Biochemistry
ID Code:2309
Deposited By: dr Adam Kawałek
Deposited On:23 Aug 2023 07:49
Last Modified:23 Aug 2023 07:49

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