{
    "abstract": "The F' plasmids ORF-1 (purE+ tsxs proC+ lac+) and F'14 (argE+ metB+ ilv+) contain active regions of recombination, fre I and fre II correspondingly. The plasmid ORF-1 is stable in recF- cells (i.e., with the RecBC pathway of recombination) and decays in rec+ cells (RecBCF pathway) giving two types of product: F+ and plasmid pCK-1 (tsxs proC+ lac+) containing part of the initial DNA. They are extremely instable in the presence of the RecF pathway, (recBC- sbcB-), yielding F+ and plasmid pCK-2 (proC+ lac+). The instability of plasmids depends on a region of homology between the chromosome and the episome. The instability of ORF-1 shows the participation of IS3 elements (alpha 1 beta 3 and alpha 3 beta 1) in the recA, recF-dependent recombinational decay and allows localization of two active sites on the chromosome: fre I1 between purE and tsx markers and fre I2 between tsx and proC. The plasmid F'14, in accordance with published data, is able to yield F+ cells by recA-independent recombination. But eventually this plasmid may undergo a recA, recF-dependent decay. Genetic analysis of these events allows localization of an active point of recombination, freII1, between argE and metB. Another active point is localized inside the F factor. The recA-dependent decay of plasmid F-14 is also excluded on the RecBC pathway (recF- strains).",
    "authors": [
        {
            "affiliation": null,
            "firstname": "S E",
            "initials": "SE",
            "lastname": "Bresler"
        },
        {
            "affiliation": null,
            "firstname": "S V",
            "initials": "SV",
            "lastname": "Krivonogov"
        },
        {
            "affiliation": null,
            "firstname": "V A",
            "initials": "VA",
            "lastname": "Lanzov"
        }
    ],
    "conclusions": null,
    "copyrights": null,
    "doi": "10.1007/BF00270161",
    "journal": "Molecular & general genetics : MGG",
    "keywords": [],
    "methods": null,
    "publication_date": "1981-01-01",
    "pubmed_id": "6276675\n333452\n368582\n6997720\n4205905\n1092667\n158459\n6248868\n5340176\n14047235\n7035814\n395413\n353291\n97269\n4615161\n395896\n4615160\n4615159\n4613608\n372972\n4615162\n383701",
    "results": null,
    "title": "Recombinational instability of F' plasmids in Escherichia coli K-12: localization of fre-sites.",
    "xml": "<Element 'PubmedArticle' at 0x788504760c20>"
}