Exploitation of the ability of the ban protein encoded by phage P1 to compensate for dnaB-defective host mutations, allowed the isolation of dnaB: :Tnl0 insertion mutations. The presence of Plbac prophage was required for survival of dnaB::TnlO mutants, and such lysogens were cryosensitive. The inse
Isolation and properties of Tn10 insertions in the rac locus of Escherichia coli
β Scribed by Binding, Ron ;Romansky, Gary ;Bitner, Rex ;Kuempel, Peter
- Publisher
- Springer
- Year
- 1981
- Tongue
- English
- Weight
- 805 KB
- Volume
- 183
- Category
- Article
- ISSN
- 0026-8925
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β¦ Synopsis
Two Tn10 insertions that are in the rac locus of the chromosome of Escherichia coli have been isolated and characterized. The insertions are located at min 29.7 and min 30.0. The insertions are stable when an F123 rac::Tn10 episome is transferred to an F- rac+ recipient, but they are lost at a high frequency when transferred to an F- rac- recipient. This latter condition has been previously demonstrated to cause the excision of the rac locus. The Tn10 insertions are also lost at a high frequency when strains containing them are lysogenized with lambda reverse. If the lysogens that have lost the Tn10 insertion are subsequently cured of lambda reverse, the cells no longer contain sequences homologous with rac locus DNA. These strains were rac- when tested for recombination activation (Low 1973), and this procedure consequently provides a simple means to make isogenic rac+ and rac- strains.
π SIMILAR VOLUMES
DNA-DNA hybridization was used to demonstrate that the substituted DNA in the bacteriophage lambda recE (formerly called lambda reverse) is homologous to DNA at the rac locus in Escherichia coli. Strains that are rac- do not contain appreciable amounts of this DNA, and it is lost from a rac+ episome
A restriction endonuclease map for the enzymes EcoRI, BamHI, SalI, and PstI covering 23.5 kilobase pairs (kb) of the srl recA region of Escherichia coli was constructed. An insertion of the transposon Tn10 in the negative regulatory gene srlR was shown to be located 5.8 kb away from the promoter pro
We have cloned the tolC gene of E. coli K-12 into pSF2124 by using transposon Tn10 as the marker to first isolate the relevant DNA fragment. The gene is on a 10.5 kb EcoRI fragment, and Tn5 insertion mutagenesis locates the gene near one end of this EcoRI fragment. An EcoRI-PstI fragment has been su
An experimental analysis of the fate of transposon Tn10 after excision from a proA::Tn10 site localized on the plasmid F' leads to the conclusions: 1. The precise excision is a progressive process. Its probability is estimated per time unit. 2. An excised Tn10 is always integrated into a different g