Skip to main content
PMC home page
Proceedings of the National Academy of Sciences of the United States of America logoLink to Proceedings of the National Academy of Sciences of the United States of America
. 1975 Aug;72(8):2905–2909. doi: 10.1073/pnas.72.8.2905

Bidirectional replication of plasmid R6K DNA in Escherichia coli; correspondence between origin of replication and position of single-strand break in relaxed complex.

M A Lovett, R B Sparks, D R Helinski
PMCID: PMC432887  PMID: 1103126

Abstract

Replicating molecules of plasmid R6K DNA have been purified as covalently closed circular DNA forms and analyzed in the electron microscopy after cleavage with the EcoRI restriction endonuclease. It has been determined that in most cases replication proceeds bidirectionally from an origin whose position is indistinguishable from the site of the single-strand break (nick) in the open circular DNA form of the relaxation complex of R6K DNA and protein. Evidence is presented for the existence of a unique replication terminus asymmetrically placed approximately 20% of genome size from the origin. The positions of the replication forks in a majority of the molecules indicate that replication proceeds sequentially from the fixed origin first in one direction to the terminus and then progresses from the origin in the other direction.

Full text

PDF
2905

Images in this article

2907Image
on p.2907
2908Image
on p.2908

Selected References

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

  1. Bourgaux P., Bourgaux-Ramoisy D. Unwinding of replicating polyoma virus DNA. J Mol Biol. 1972 Oct 14;70(3):399–413. doi: 10.1016/0022-2836(72)90548-7. [DOI] [PubMed] [Google Scholar]
  2. 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]
  3. Fareed G. C., Garon G. F., Salzman N. P. Origin and direction of simian virus 40 deoxyribonucleic acid replication. J Virol. 1972 Sep;10(3):484–491. doi: 10.1128/jvi.10.3.484-491.1972. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Guerry P., LeBlanc D. J., Falkow S. General method for the isolation of plasmid deoxyribonucleic acid. J Bacteriol. 1973 Nov;116(2):1064–1066. doi: 10.1128/jb.116.2.1064-1066.1973. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Gyurasits E. B., Wake R. G. Bidirectional chromosome replication in Bacillus subtilis. J Mol Biol. 1973 Jan;73(1):55–63. doi: 10.1016/0022-2836(73)90158-7. [DOI] [PubMed] [Google Scholar]
  6. Helinski D. R. Plasmid determined resistance to antibiotics: molecular properties of R factors. Annu Rev Microbiol. 1973;27:437–470. doi: 10.1146/annurev.mi.27.100173.002253. [DOI] [PubMed] [Google Scholar]
  7. Hershfield V., Boyer H. W., Yanofsky C., Lovett M. A., Helinski D. R. Plasmid ColEl as a molecular vehicle for cloning and amplification of DNA. Proc Natl Acad Sci U S A. 1974 Sep;71(9):3455–3459. doi: 10.1073/pnas.71.9.3455. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Hirt B. Selective extraction of polyoma DNA from infected mouse cell cultures. J Mol Biol. 1967 Jun 14;26(2):365–369. doi: 10.1016/0022-2836(67)90307-5. [DOI] [PubMed] [Google Scholar]
  9. Jaenisch R., Mayer A., Levine A. Replicating SV40 molecules containing closed circular template DNA strands. Nat New Biol. 1971 Sep 15;233(37):72–75. doi: 10.1038/newbio233072a0. [DOI] [PubMed] [Google Scholar]
  10. Kontomichalou P., Mitani M., Clowes R. C. Circular R-factor molecules controlling penicillinase synthesis, replicating in Escherichia coli under either relaxed or stringent control. J Bacteriol. 1970 Oct;104(1):34–44. doi: 10.1128/jb.104.1.34-44.1970. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Kupersztoch-Portnoy Y. M., Lovett M. A., Helinski D. R. Strand and site specificity of the relaxation event for the relaxation complex of the antibiotic resistance plasmid R6K. Biochemistry. 1974 Dec 31;13(27):5484–5490. doi: 10.1021/bi00724a005. [DOI] [PubMed] [Google Scholar]
  12. Kupersztoch Y. M., Helinski D. R. A catenated DNA molecule as an intermediate in the replication of the resistance transfer factor R6K in Escherichia coli. Biochem Biophys Res Commun. 1973 Oct 15;54(4):1451–1459. doi: 10.1016/0006-291x(73)91149-2. [DOI] [PubMed] [Google Scholar]
  13. Lovett M. A., Guiney D. G., Helinski D. R. Relaxation complexes of plasmids ColE1 and ColE2: unique site of the nick in the open circular DNA of the relaxed complexes. Proc Natl Acad Sci U S A. 1974 Oct;71(10):3854–3857. doi: 10.1073/pnas.71.10.3854. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Lovett M. A., Katz L., Helinski D. R. Unidirectional replication of plasmid ColE1 DNA. Nature. 1974 Sep 27;251(5473):337–340. doi: 10.1038/251337a0. [DOI] [PubMed] [Google Scholar]
  15. Masters M., Broda P. Evidence for the bidirectional replications of the Escherichia coli chromosome. Nat New Biol. 1971 Aug 4;232(31):137–140. doi: 10.1038/newbio232137a0. [DOI] [PubMed] [Google Scholar]
  16. Nishioka Y., Eisenstark A. Sequence of genes replicated in Salmonella typhimurium as examined by transduction techniques. J Bacteriol. 1970 May;102(2):320–333. doi: 10.1128/jb.102.2.320-333.1970. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Rodriguez R. L., Dalbey M. S., Davern C. I. Autoradiographic evidence for bidirectional DNA replication in Escherichia coli. J Mol Biol. 1973 Mar 15;74(4):599–604. doi: 10.1016/0022-2836(73)90050-8. [DOI] [PubMed] [Google Scholar]
  18. Schnös M., Inman R. B. Position of branch points in replicating lambda DNA. J Mol Biol. 1970 Jul 14;51(1):61–73. doi: 10.1016/0022-2836(70)90270-6. [DOI] [PubMed] [Google Scholar]

Articles from Proceedings of the National Academy of Sciences of the United States of America are provided here courtesy of National Academy of Sciences

RESOURCES