P1 Plasmid Segregation: Accurate Redistribution by Dynamic Plasmid Pairing and Separation
- 1 March 2010
- journal article
- research article
- Published by American Society for Microbiology in Journal of Bacteriology
- Vol. 192 (5), 1175-1183
- https://doi.org/10.1128/jb.01245-09
Abstract
Low-copy-number plasmids, such as P1 and F, encode a type Ia partition system (P1 par or F sop ) for active segregation of copies to daughter cells. Typical descriptions show a single central plasmid focus dividing and the products moving to the cell quarter regions, ensuring segregation. However, using improved optical and analytical tools and large cell populations, we show that P1 plasmid foci are very broadly distributed. Moreover, under most growth conditions, more than two foci are frequently present. Each focus contains either one or two plasmid copies. Replication and focus splitting occur at almost any position in the cell. The products then move rapidly apart for approximately 40% of the cell length. They then tend to maintain their relative positions. The segregating foci often pass close to or come to rest close to other foci in the cell. Foci frequently appear to fuse during these encounters. Such events occur several times in each cell and cell generation on average. We argue that foci pair with their neighbors and then actively separate again. The net result is an approximately even distribution of foci along the long cell axis on average. We show mathematically that trans -pairing and active separation could greatly increase the accuracy of segregation and would produce the distributions of foci that we observe. Plasmid pairing and separation may constitute a novel fine-tuning mechanism that takes the basic pattern created when plasmids separate after replication and converts it to a roughly even pattern that greatly improves the fidelity of plasmid segregation.Keywords
This publication has 42 references indexed in Scilit:
- F plasmid partition depends on interaction of SopA with non‐specific DNAMolecular Microbiology, 2008
- Oscillating focus of SopA associated with filamentous structure guides partitioning of F plasmidMolecular Microbiology, 2007
- P1 Partition Complex Assembly Involves Several Modes of Protein-DNA RecognitionPublished by Elsevier BV ,2007
- Regular cellular distribution of plasmids by oscillating and filament‐forming ParA ATPase of plasmid pB171Molecular Microbiology, 2006
- Progressive segregation of the Escherichia coli chromosomeMolecular Microbiology, 2006
- Subcellular Positioning of F Plasmid Mediated by Dynamic Localization of SopA and SopBJournal of Molecular Biology, 2006
- Bacterial mitosis: partitioning protein ParA oscillates in spiral‐shaped structures and positions plasmids at mid‐cellMolecular Microbiology, 2004
- Kinetics of plasmid segregation in Escherichia coliMolecular Microbiology, 2004
- Analysis of Relative Gene Expression Data Using Real-Time Quantitative PCR and the 2−ΔΔCT MethodMethods, 2001
- Topological Scanning of the P1 Plasmid Partition SiteJournal of Molecular Biology, 1994