Skip to main content
PMC home page
The EMBO Journal logoLink to The EMBO Journal
. 1986 Aug;5(8):2023–2029. doi: 10.1002/j.1460-2075.1986.tb04459.x

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.

K Gerdes, F W Bech, S T Jørgensen, A Løbner-Olesen, P B Rasmussen, T Atlung, L Boe, O Karlstrom, S Molin, K von Meyenburg
PMCID: PMC1167073  PMID: 3019679

Abstract

The parB region of plasmid R1 encodes two genes, hok and sok, which are required for the plasmid-stabilizing activity exerted by parB. The hok gene encodes a potent cell-killing factor, and it is regulated by the sok gene product such that cells losing a parB-carrying plasmid during cell division are rapidly killed. Coinciding with death of the host cell, a characteristic change in morphology is observed. Here we show that the killing factor encoded by the hok gene is a membrane-associated polypeptide of 52 amino acids. A gene located in the Escherichia coli relB operon, designated relF, is shown to be homologous to the hok gene. The relF gene codes for a polypeptide of 51 amino acids, which is 40% homologous to the hok gene product. Induced overexpression of the hok and relF gene products results in the same phenomena: loss of cell membrane potential, arrest of respiration, death of the host cell and change in cell morphology. The parB region and the relB genes were cloned into unstably inherited oriC minichromosomes. Whereas the parB region also conferred a high degree of genetic stability to an oriC minichromosome, the relB operon (with relF) did not; therefore the latter does not appear to 'stabilize' its replicon (the chromosome). The function of the relF gene is not known.

Full text

PDF
2029

Images in this article

2024Fig. 3.
on p.2024
2026Fig. 7.
on p.2026

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Bachmann B. J. Pedigrees of some mutant strains of Escherichia coli K-12. Bacteriol Rev. 1972 Dec;36(4):525–557. doi: 10.1128/br.36.4.525-557.1972. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Bech F. W., Jørgensen S. T., Diderichsen B., Karlström O. H. Sequence of the relB transcription unit from Escherichia coli and identification of the relB gene. EMBO J. 1985 Apr;4(4):1059–1066. doi: 10.1002/j.1460-2075.1985.tb03739.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Birnboim H. C., Doly J. A rapid alkaline extraction procedure for screening recombinant plasmid DNA. Nucleic Acids Res. 1979 Nov 24;7(6):1513–1523. doi: 10.1093/nar/7.6.1513. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Bolivar F., Rodriguez R. L., Greene P. J., Betlach M. C., Heyneker H. L., Boyer H. W., Crosa J. H., Falkow S. Construction and characterization of new cloning vehicles. II. A multipurpose cloning system. Gene. 1977;2(2):95–113. [PubMed] [Google Scholar]
  5. Cohen S. N., Chang A. C., Hsu L. Nonchromosomal antibiotic resistance in bacteria: genetic transformation of Escherichia coli by R-factor DNA. Proc Natl Acad Sci U S A. 1972 Aug;69(8):2110–2114. doi: 10.1073/pnas.69.8.2110. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Figurski D. H., Pohlman R. F., Bechhofer D. H., Prince A. S., Kelton C. A. Broad host range plasmid RK2 encodes multiple kil genes potentially lethal to Escherichia coli host cells. Proc Natl Acad Sci U S A. 1982 Mar;79(6):1935–1939. doi: 10.1073/pnas.79.6.1935. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Gerdes K., Larsen J. E., Molin S. Stable inheritance of plasmid R1 requires two different loci. J Bacteriol. 1985 Jan;161(1):292–298. doi: 10.1128/jb.161.1.292-298.1985. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Gerdes K., Rasmussen P. B., Molin S. Unique type of plasmid maintenance function: postsegregational killing of plasmid-free cells. Proc Natl Acad Sci U S A. 1986 May;83(10):3116–3120. doi: 10.1073/pnas.83.10.3116. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Gilson E., Clément J. M., Brutlag D., Hofnung M. A family of dispersed repetitive extragenic palindromic DNA sequences in E. coli. EMBO J. 1984 Jun;3(6):1417–1421. doi: 10.1002/j.1460-2075.1984.tb01986.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Hall M. N., Silhavy T. J. Genetic analysis of the major outer membrane proteins of Escherichia coli. Annu Rev Genet. 1981;15:91–142. doi: 10.1146/annurev.ge.15.120181.000515. [DOI] [PubMed] [Google Scholar]
  11. Hirota N., Matsuura S., Mochizuki N., Mutoh N., Imae Y. Use of lipophilic cation-permeable mutants for measurement of transmembrane electrical potential in metabolizing cells of Escherichia coli. J Bacteriol. 1981 Nov;148(2):399–405. doi: 10.1128/jb.148.2.399-405.1981. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Hopp T. P., Woods K. R. Prediction of protein antigenic determinants from amino acid sequences. Proc Natl Acad Sci U S A. 1981 Jun;78(6):3824–3828. doi: 10.1073/pnas.78.6.3824. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Jaffé A., Ogura T., Hiraga S. Effects of the ccd function of the F plasmid on bacterial growth. J Bacteriol. 1985 Sep;163(3):841–849. doi: 10.1128/jb.163.3.841-849.1985. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Messer W., Bergmans H. E., Meijer M., Womack J. E., Hansen F. G., von Meyenburg K. Mini-chromosomes: plasmids which carry the E. coli replication origin. Mol Gen Genet. 1978 Jul 4;162(3):269–275. doi: 10.1007/BF00268852. [DOI] [PubMed] [Google Scholar]
  15. Nordström K., Aagaard-Hansen H. Maintenance of bacterial plasmids: comparison of theoretical calculations and experiments with plasmid R1 in Escherichia coli. Mol Gen Genet. 1984;197(1):1–7. doi: 10.1007/BF00327915. [DOI] [PubMed] [Google Scholar]
  16. Nordström K., Molin S., Aagaard-Hansen H. Partitioning of plasmid R1 in Escherichia coli. I. Kinetics of loss of plasmid derivatives deleted of the par region. Plasmid. 1980 Sep;4(2):215–227. doi: 10.1016/0147-619x(80)90011-6. [DOI] [PubMed] [Google Scholar]
  17. Phillips R. D. A method for the rapid, automated filtration of protein hydrolyzates. Anal Biochem. 1981 Nov 15;118(1):91–95. doi: 10.1016/0003-2697(81)90161-5. [DOI] [PubMed] [Google Scholar]
  18. Remaut E., Stanssens P., Fiers W. Plasmid vectors for high-efficiency expression controlled by the PL promoter of coliphage lambda. Gene. 1981 Oct;15(1):81–93. doi: 10.1016/0378-1119(81)90106-2. [DOI] [PubMed] [Google Scholar]
  19. Russel M., Model P. Filamentous phage pre-coat is an integral membrane protein: analysis by a new method of membrane preparation. Cell. 1982 Jan;28(1):177–184. doi: 10.1016/0092-8674(82)90387-7. [DOI] [PubMed] [Google Scholar]
  20. Sancar A., Hack A. M., Rupp W. D. Simple method for identification of plasmid-coded proteins. J Bacteriol. 1979 Jan;137(1):692–693. doi: 10.1128/jb.137.1.692-693.1979. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Sekiguchi M., Iida S. Mutants of Escherichia coli permeable to actinomycin. Proc Natl Acad Sci U S A. 1967 Dec;58(6):2315–2320. doi: 10.1073/pnas.58.6.2315. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Shine J., Dalgarno L. The 3'-terminal sequence of Escherichia coli 16S ribosomal RNA: complementarity to nonsense triplets and ribosome binding sites. Proc Natl Acad Sci U S A. 1974 Apr;71(4):1342–1346. doi: 10.1073/pnas.71.4.1342. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Stragier P., Bouvier J., Bonamy C., Szulmajster J. A developmental gene product of Bacillus subtilis homologous to the sigma factor of Escherichia coli. Nature. 1984 Nov 22;312(5992):376–378. doi: 10.1038/312376a0. [DOI] [PubMed] [Google Scholar]
  24. Young C., Prince A. S., Figurski D. H. korA function of promiscuous plasmid RK2: an autorepressor that inhibits expression of host-lethal gene kilA and replication gene trfA. Proc Natl Acad Sci U S A. 1985 Nov;82(21):7374–7378. doi: 10.1073/pnas.82.21.7374. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. von Meyenburg K., Hansen F. G., Riise E., Bergmans H. E., Meijer M., Messer W. Origin of replication, oriC, of the Escherichia coli K12 chromosome: genetic mapping and minichromosome replication. Cold Spring Harb Symp Quant Biol. 1979;43(Pt 1):121–128. doi: 10.1101/sqb.1979.043.01.018. [DOI] [PubMed] [Google Scholar]
  26. von Meyenburg K., Jørgensen B. B., Michelsen O., Sørensen L., McCarthy J. E. Proton conduction by subunit a of the membrane-bound ATP synthase of Escherichia coli revealed after induced overproduction. EMBO J. 1985 Sep;4(9):2357–2363. doi: 10.1002/j.1460-2075.1985.tb03939.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. von Meyenburg K., Jørgensen B. B., Nielsen J., Hansen F. G. Promoters of the atp operon coding for the membrane-bound ATP synthase of Escherichia coli mapped by Tn10 insertion mutations. Mol Gen Genet. 1982;188(2):240–248. doi: 10.1007/BF00332682. [DOI] [PubMed] [Google Scholar]

Articles from The EMBO Journal are provided here courtesy of Nature Publishing Group

RESOURCES