In matings between F' donors and recombination-deficient Hfr recipients, we isolated progeny which transferred both episomal markers and Hfr markers early and with high frequency. A number of these progeny had two integrated sex factors. Investigation of these double Hfr strains showed that the F' nearly always integrated in a homologous region of the chromosome. In any particular mating system integration was specific as to location and direction of chromosome transfer.
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http://dx.doi.org/10.1128/jb.106.1.150-156.1971 | DOI Listing |
FEMS Microbiol Lett
May 1999
Department of Chemical and Environmental Science, University of Limerick, Ireland.
The integration site(s) of the IncJ element, R391, was localised to a specific region of the Escherichia coli chromosome, between the uxuA and serB loci (98.0-99.5 min), using classical Hfr mapping techniques.
View Article and Find Full Text PDFFEMS Microbiol Lett
December 1995
Department of Chemical and Environment Science, University of Limerick, Ireland.
A study of the IncJ plasmid R391 confirmed a low frequency of transfer between recombination proficient (recA+) Escherichia coli (10(-5) donor -1). Reanalysis of its transfer to recombination deficient (recA) E. coli revealed an equivalent transfer frequency to and from all mutants tested.
View Article and Find Full Text PDFMol Gen Genet
April 1989
Department of Genetics, University of Nottingham, Queens Medical Centre, UK.
A new recombination gene called recR has been identified and located near dnaZ at minute 11 on the current linkage map of Escherichia coli. The gene was detected after transposon mutagenesis of a recB sbcB strain and screening for insertion mutants that had a reduced efficiency of recombination in Hfr crosses. The recR insertions obtained conferred a recombination deficient and extremely UV sensitive phenotype in both recB recC sbcA and recB recC sbcB sbcC genetic backgrounds.
View Article and Find Full Text PDFBroad host range IncP-1 plasmids are able to integrate into the chromosome of gram-negative bacteria. Strains carrying an integrated plasmid can be obtained when the markers of a temperature-sensitive (ts) plasmid derivative are selected at non-permissive temperature; in this way Hfr (high frequency) donor strains can be formed. The integrated plasmids, however, tend to be unstable in the absence of continuous selective pressure.
View Article and Find Full Text PDFWe have developed an experimental system for studying concomitantly the fate of the donor DNA and the process of recombination after conjugation in Escherichia coli. We used a set of Hfr and F-strains carrying complementing lacZ mutations. Expression of the lacZ allele on the chromosomal fragment derived from the donor results in the formation of heat sensitive beta-galactosidase by complementation.
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