• We are sorry, but NCBI web applications do not support your browser and may not function properly. More information
Logo of embojLink to Publisher's site
EMBO J. Aug 1986; 5(8): 2023–2029.
PMCID: PMC1167073

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.

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

Full text is available as a scanned copy of the original print version. Get a printable copy (PDF file) of the complete article (1.3M), or click on a page image below to browse page by page. Links to PubMed are also available for Selected References.

Images in this article

Click on the image to see a larger version.

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Bachmann BJ. Pedigrees of some mutant strains of Escherichia coli K-12. Bacteriol Rev. 1972 Dec;36(4):525–557. [PMC free article] [PubMed]
  • Bech FW, Jørgensen ST, Diderichsen B, Karlström OH. Sequence of the relB transcription unit from Escherichia coli and identification of the relB gene. EMBO J. 1985 Apr;4(4):1059–1066. [PMC free article] [PubMed]
  • Birnboim HC, Doly J. A rapid alkaline extraction procedure for screening recombinant plasmid DNA. Nucleic Acids Res. 1979 Nov 24;7(6):1513–1523. [PMC free article] [PubMed]
  • Bolivar F, Rodriguez RL, Greene PJ, Betlach MC, Heyneker HL, Boyer HW, Crosa JH, Falkow S. Construction and characterization of new cloning vehicles. II. A multipurpose cloning system. Gene. 1977;2(2):95–113. [PubMed]
  • Cohen SN, Chang AC, 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. [PMC free article] [PubMed]
  • Figurski DH, Pohlman RF, Bechhofer DH, Prince AS, Kelton CA. 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. [PMC free article] [PubMed]
  • Gerdes K, Larsen JE, Molin S. Stable inheritance of plasmid R1 requires two different loci. J Bacteriol. 1985 Jan;161(1):292–298. [PMC free article] [PubMed]
  • Gerdes K, Rasmussen PB, 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. [PMC free article] [PubMed]
  • Gilson E, Clément JM, Brutlag D, Hofnung M. A family of dispersed repetitive extragenic palindromic DNA sequences in E. coli. EMBO J. 1984 Jun;3(6):1417–1421. [PMC free article] [PubMed]
  • Hall MN, Silhavy TJ. Genetic analysis of the major outer membrane proteins of Escherichia coli. Annu Rev Genet. 1981;15:91–142. [PubMed]
  • 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. [PMC free article] [PubMed]
  • Hopp TP, Woods KR. Prediction of protein antigenic determinants from amino acid sequences. Proc Natl Acad Sci U S A. 1981 Jun;78(6):3824–3828. [PMC free article] [PubMed]
  • 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. [PMC free article] [PubMed]
  • Messer W, Bergmans HE, Meijer M, Womack JE, Hansen FG, von Meyenburg K. Mini-chromosomes: plasmids which carry the E. coli replication origin. Mol Gen Genet. 1978 Jul 4;162(3):269–275. [PubMed]
  • 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. [PubMed]
  • 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. [PubMed]
  • 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. [PubMed]
  • 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. [PubMed]
  • Sancar A, Hack AM, Rupp WD. Simple method for identification of plasmid-coded proteins. J Bacteriol. 1979 Jan;137(1):692–693. [PMC free article] [PubMed]
  • Sekiguchi M, Iida S. Mutants of Escherichia coli permeable to actinomycin. Proc Natl Acad Sci U S A. 1967 Dec;58(6):2315–2320. [PMC free article] [PubMed]
  • 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. [PMC free article] [PubMed]
  • Phillips RD. A method for the rapid, automated filtration of protein hydrolyzates. Anal Biochem. 1981 Nov 15;118(1):91–95. [PubMed]
  • 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. [PubMed]
  • von Meyenburg K, Hansen FG, Riise E, Bergmans HE, 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. [PubMed]
  • von Meyenburg K, Jørgensen BB, Nielsen J, Hansen FG. 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. [PubMed]
  • von Meyenburg K, Jørgensen BB, Michelsen O, Sørensen L, McCarthy JE. 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. [PMC free article] [PubMed]
  • Young C, Prince AS, Figurski DH. 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. [PMC free article] [PubMed]

Articles from The EMBO Journal are provided here courtesy of The European Molecular Biology Organization

Formats:

Related citations in PubMed

See reviews...See all...

Cited by other articles in PMC

See all...

Links

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...