Abstract
The parB locus of plasmid R1, comprising at most 580 base pairs of DNA, mediates efficient plasmid stabilization via postsegregational killing of plasmid free cells. The locus encodes two small genes, hok and sok. The hok gene product is a potent cell killing protein, the expression of which is regulated by the sok product, an anti-sense RNA complementary to the hok mRNA. The hok mRNA is extraordinarily stable, while the sok-RNA is rapidly degraded. The mechanism of postsegregational killing is explained by the differential decay of the hok and sok-RNA's: In newborn plasmid free cells the prolonged persistence of the hok mRNA leads to synthesis of the Hok protein, thus ensuring a rapid and selective killing of these cells. As predicted from this simple model, any unstably inherited plasmid should become stabilized by carrying the parB locus. This important prediction was confirmed by testing a variety of different replicons. Even plasmids replicating in as distantly related organisms as Eschericia coli, Serratia marsescense, and Pseudomonas putida were efficiently stabilized. The parB locus therefore constitutes a convenient and efficient plasmid stabilization casette, useful in many gram negative species.
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References
Skogman, G., Nilsson, J. and Gustafsson, P. 1983. The use of a partitioning locus to increase stability of tryptophan-operon bearing plasmids in E. coli . Gene 23:105–115.
Diderichsen, B. 1986. A genetic system for stabilization of cloned genes in Bacillus subtilis, 35–46. In: Bacillus Molecular Genetics and Biotechnology Applications. A. T. Ganesan and J. A. Hoch. (Eds.) Academic Press, Orlando, FL.
Gerdes, K., Larsen, J.E.L., and Molin, S. 1985. Stable inheritance of plasmid R1 requires two different loci. J. Bacteriol. 161:292–298.
Gerdes, K., Rasmussen, P.B., and Molin, S. 1986. Unique type of plasmid maintenance function: Postsegregational killing of plasmid free cells. Proc. Natl. Acad. Sci. USA. 83:3116–3120.
Rasmussen, P.B., Gerdes, K., and Molin, S. 1987. Genetic analysis of the parB locus of plasmid R1. Mol. Gen. Genet. 209:122–128.
Gerdes, K., Bech, F.W., Jørgensen, S.T., Løbner-Olesen, A., Rasmussen, P.B., Atlung, T., Karlstrøm, O., Molin, S., and von Meyenburg, K. 1986. Mechanism of postsegregational killing by the hok gene product of the parB system of plasmid R1 and its homology with the relF gene product of the E. coli relB operon. EMBO J. 5:2023–2029.
Gerdes, K., Helin, K., Christensen, O.W., and Løbner-Olesen, A. 1988. Translational control and differential RNA decay are key elements in regulating postsegregational expression of the killer protein encoded by the parB locus of plasmid R1. J. Mol. Biol. 203:119–129.
Molin, S., Klemm, P., Poulsen, L.K., Biehl, H., Gerdes, K., and Andersson, P. 1987. Conditional suicide system for containment of bacteria and plasmids. Bio/Technology 5:901–903.
Ogura, T., and Hiraga, S. 1983. Mini-F plasmid genes that couple host cell division to plasmid proliferation. Proc. Natl. Acad. Sci. USA. 80:4784–4788.
Miki, T., Yoshioka, K., and Horiuchi, T. 1984. Control of cell division by sex factor F in E. coli: I. The 42.84–43.6 F segment couples cell division of the host bacteria with replication of plasmid DNA. J. Mol. Biol. 174:605–625.
Jaffe, A., Ogura, T., and Hiraga, S. 1985. Effects of the ccd function of the F plasmid on bacteriol growth. J. Bacteriol. 163:841–849.
Hiraga, S., Jaffe, A., Ogura, T., Mori, H., and Takahashi, H. 1986. F plasmid ccd mechanism in E. coli . J. Bacteriol. 166:100–104.
Boe, L., Gerdes, K., and Molin, S. 1987. The effects of genes exerting growth inhibition and plasmid maintenance on plasmid stability. J. Bacteriol. 169:4646–4650.
Golub, E.I., and Low, K.B. 1986. Unrelated conjugative plasmids have sequences which are homologous to the leading region of the F factor. J. Bacteriol. 166:670–672.
Ray, A., and Skurray, R. 1984. Stabilization of the cloning vector pACYC184 by insertion of F plasmid leading region sequences. Plasmid 11:272–275.
Blohm, D., and Goebel, W. 1978. Restriction map of the antibiotic resistance plasmid R1drd-19 and its derivatives pKN102 (R1drd-19B2) and R1drd-16 for the enzymes BamHI, HindIII, EcoRI, and SalI. Mol. Gen. Genet. 167:119–127.
Clerget, M., Chandler, M., and Caro, L. 1981. The structure of R1drd-19: A revised physical map of the plasmid. Mol. Gen. Genet. 181:183–191.
Gerdes, K., and Molin, S. 1986. Partitioning of plasmid R1: Structural and functional analysis of the parA locus. J. Mol. Biol. 190:269–279.
Nordström, K. and Aagaard-Hansen, H. 1984. Maintenance of bacterial plasmids: Comparison of theoretical calculations and experiments with plasmid R1 in Escherichia coli . Mol. Gen. Genet. 197:1–7.
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Gerdes, K. The parB (hok/sok) Locus of Plasmid R1: A General Purpose Plasmid Stabilization System. Nat Biotechnol 6, 1402–1405 (1988). https://doi.org/10.1038/nbt1288-1402
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DOI: https://doi.org/10.1038/nbt1288-1402
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