Open AccessA conserved mechanism drives partition complex assembly on bacterial chromosomes and plasmids
Author(s) -
Debaugny Roxanne E,
Sanchez Aurore,
Rech Jérôme,
Labourdette Delphine,
Dorignac Jérôme,
Geniet Frédéric,
Palmeri John,
Parmeggiani Andrea,
Boudsocq François,
Anton Leberre Véronique,
Walter JeanCharles,
Bouet JeanYves
Publication year - 2018
Publication title -
molecular systems biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 8.523
H-Index - 148
ISSN - 1744-4292
DOI - 10.15252/msb.20188516
Subject(s) - biology , plasmid , chromosome segregation , caulobacter crescentus , genetics , dna , centromere , nucleoid , origin of replication , chromosome , nucleoprotein , transcription (linguistics) , computational biology , microbiology and biotechnology , biophysics , bacteria , escherichia coli , gene , bacterial protein , linguistics , philosophy
Chromosome and plasmid segregation in bacteria are mostly driven by ParAB S systems. These DNA partitioning machineries rely on large nucleoprotein complexes assembled on centromere sites ( parS ). However, the mechanism of how a few parS ‐bound ParB proteins nucleate the formation of highly concentrated ParB clusters remains unclear despite several proposed physico‐mathematical models. We discriminated between these different models by varying some key parameters in vivo using the F plasmid partition system. We found that “Nucleation & caging” is the only coherent model recapitulating in vivo data. We also showed that the stochastic self‐assembly of partition complexes (i) is a robust mechanism, (ii) does not directly involve ParA ATP ase, (iii) results in a dynamic structure of discrete size independent of ParB concentration, and (iv) is not perturbed by active transcription but is by protein complexes. We refined the “Nucleation & caging” model and successfully applied it to the chromosomally encoded Par system of Vibrio cholerae , indicating that this stochastic self‐assembly mechanism is widely conserved from plasmids to chromosomes.