Two replication initiation sites on R-plasmid DNA

Jorge H. Crosa, Linda K. Luttropp, Fred Heffron, Stanley Falkow

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31 Scopus citations


Replicating DNA molecules of a deletion mutant of the conjugative R-plasmid R 6 K are cleaved at a single site by the EcoRI restriction endonuclease. Electron microscope examination and measurements of the EcoRI treated replicative intermediate molecules indicate that replication can be initiated at two sites on the plasmid DNA molecule. The two sites are located at about 23 and 39% of total length, respectively, from the EcoRI cleavage site. About 5% of the replicating molecules use both replication initiation sites simultaneously.

Original languageEnglish (US)
Pages (from-to)39-50
Number of pages12
JournalMGG Molecular & General Genetics
Issue number1
Publication statusPublished - Mar 1975
Externally publishedYes


ASJC Scopus subject areas

  • Genetics

Cite this

Crosa, J. H., Luttropp, L. K., Heffron, F., & Falkow, S. (1975). Two replication initiation sites on R-plasmid DNA. MGG Molecular & General Genetics, 140(1), 39-50.