microbiology, Vol 144, 3369-3378, Copyright © 1998 by Society for General Microbiology

ARTICLES

The partitioning activity of the RK2 central control region requires only incC, korB and KorB-binding site O(B)3 but other KorB-binding sites form destabilizing complexes in the absence of O(B)3

DR Williams, DP Macartney and CM Thomas
School of Biological Sciences, The University of Birmingham, Edgbaston, UK.

The sector of the genome of broad-host-range IncP plasmid RK2 from kb coordinate 54.0 to 60.0 confers an active partitioning phenotype, increasing the segregational stability of low-copy-number unstable plasmids. This Par region encodes the central control operon (korA, incC, korB, korF and korG) and the associated genes kfrA, upf54.8 and upf54.4. Each ORF in this region was knocked out in turn and it was shown that only incC and korB are needed for the stability phenotype. incC encodes two polypeptides from alternative translational starts. A deletion of the start of the operon showed that only IncC2, the shorter product, is essential for partitioning. Directed mutation or deletion was used to inactivate in turn each of the three KorB-binding sites (O(B)s) which were candidate cis-acting sequences needed for stability. Only inactivation of O(B)3, which lies between upf54.4 and upf54.8, resulted in an increased rate of segregational loss. However, the rate of loss was significantly higher than the rate of loss of the test plasmid carrying none of this RK2 Par region. Either inactivation of korB or deletion of O(B)1 from this O(B)3 mutant resulted in restoration of the loss rate to that expected for the unstable test plasmid alone. Thus KorB can act on O(B)1 to create a complex that either inhibits replication or reduces the effective plasmid copy number, perhaps by promoting pairing between plasmid molecules. This implies that RK2 goes through a cycle of pairing and separation, akin to the mitotic cycle of eukaryotic chromosomes.

This article has been cited by other articles:

				K. Kolatka, M. Witosinska, M. Pierechod, and I. Konieczny Bacterial partitioning proteins affect the subcellular location of broad-host-range plasmid RK2 Microbiology, September 1, 2008; 154(9): 2847 - 2856. [Abstract] [Full Text] [PDF]

				D. Bartosik, M. Putyrski, L. Dziewit, E. Malewska, M. Szymanik, E. Jagiello, J. Lukasik, and J. Baj Transposable Modules Generated by a Single Copy of Insertion Sequence ISPme1 and Their Influence on Structure and Evolution of Natural Plasmids of Paracoccus methylutens DM12 J. Bacteriol., May 1, 2008; 190(9): 3306 - 3313. [Abstract] [Full Text] [PDF]

				J. Livny, Y. Yamaichi, and M. K. Waldor Distribution of Centromere-Like parS Sites in Bacteria: Insights from Comparative Genomics J. Bacteriol., December 1, 2007; 189(23): 8693 - 8703. [Abstract] [Full Text] [PDF]

				Y. Yamaichi, M. A. Fogel, S. M. McLeod, M. P. Hui, and M. K. Waldor Distinct Centromere-Like parS Sites on the Two Chromosomes of Vibrio spp. J. Bacteriol., July 15, 2007; 189(14): 5314 - 5324. [Abstract] [Full Text] [PDF]

				S. Yao, D. R. Helinski, and A. Toukdarian Localization of the Naturally Occurring Plasmid ColE1 at the Cell Pole J. Bacteriol., March 1, 2007; 189(5): 1946 - 1953. [Abstract] [Full Text] [PDF]

				M. Dmowski, I. Sitkiewicz, and P. Ceglowski Characterization of a Novel Partition System Encoded by the {delta} and {omega} Genes from the Streptococcal Plasmid pSM19035. J. Bacteriol., June 1, 2006; 188(12): 4362 - 4372. [Abstract] [Full Text] [PDF]

				M. Adamczyk, P. Dolowy, M. Jonczyk, C. M. Thomas, and G. Jagura-Burdzy The kfrA gene is the first in a tricistronic operon required for survival of IncP-1 plasmid R751 Microbiology, June 1, 2006; 152(6): 1621 - 1637. [Abstract] [Full Text] [PDF]

				M. Mikosa, M. Sochacka-Pietal, J. Baj, and D. Bartosik Identification of a transposable genomic island of Paracoccus pantotrophus DSM 11072 by its transposition to a novel entrapment vector pMMB2. Microbiology, April 1, 2006; 152(Pt 4): 1063 - 1073. [Abstract] [Full Text] [PDF]

				M. B. Lobocka, D. J. Rose, G. Plunkett III, M. Rusin, A. Samojedny, H. Lehnherr, M. B. Yarmolinsky, and F. R. Blattner Genome of Bacteriophage P1 J. Bacteriol., November 1, 2004; 186(21): 7032 - 7068. [Abstract] [Full Text] [PDF]

				A. A. Bartosik, K. Lasocki, J. Mierzejewska, C. M. Thomas, and G. Jagura-Burdzy ParB of Pseudomonas aeruginosa: Interactions with Its Partner ParA and Its Target parS and Specific Effects on Bacterial Growth J. Bacteriol., October 15, 2004; 186(20): 6983 - 6998. [Abstract] [Full Text] [PDF]

				D. Bartosik, J. Baj, A. A. Bartosik, and M. Wlodarczyk Characterization of the replicator region of megaplasmid pTAV3 of Paracoccus versutus and search for plasmid-encoded traits Microbiology, March 1, 2002; 148(3): 871 - 881. [Abstract] [Full Text] [PDF]

				M. Lukaszewicz, K. Kostelidou, A. A. Bartosik, G. D. Cooke, C. M. Thomas, and G. Jagura-Burdzy Functional dissection of the ParB homologue (KorB) from IncP-1 plasmid RK2 Nucleic Acids Res., February 15, 2002; 30(4): 1046 - 1055. [Abstract] [Full Text] [PDF]

				R. A. Lewis, C. R. Bignell, W. Zeng, A. C. Jones, and C. M. Thomas Chromosome loss from par mutants of Pseudomonas putida depends on growth medium and phase of growth Microbiology, February 1, 2002; 148(2): 537 - 548. [Abstract] [Full Text] [PDF]

				H. Delbruck, G. Ziegelin, E. Lanka, and U. Heinemann An Src Homology 3-like Domain Is Responsible for Dimerization of the Repressor Protein KorB Encoded by the Promiscuous IncP Plasmid RP4 J. Biol. Chem., February 1, 2002; 277(6): 4191 - 4198. [Abstract] [Full Text] [PDF]

				T. M. Rosche, A. Siddique, M. H. Larsen, and D. H. Figurski Incompatibility Protein IncC and Global Regulator KorB Interact in Active Partition of Promiscuous Plasmid RK2 J. Bacteriol., November 1, 2000; 182(21): 6014 - 6026. [Abstract] [Full Text]

				N. Ravin and D. Lane Partition of the Linear Plasmid N15: Interactions of N15 Partition Functions with the sop Locus of the F Plasmid J. Bacteriol., November 15, 1999; 181(22): 6898 - 6906. [Abstract] [Full Text]

				G. Jagura-Burdzy, K. Kostelidou, J. Pole, D. Khare, A. Jones, D. R. Williams, and C. M. Thomas IncC of Broad-Host-Range Plasmid RK2 Modulates KorB Transcriptional Repressor Activity In Vivo and Operator Binding In Vitro J. Bacteriol., May 1, 1999; 181(9): 2807 - 2815. [Abstract] [Full Text]