ISSN:
1617-4623
Schlagwort(e):
Escherichia coli
;
Short homology
;
Direct repeat
;
Spi− phenotype
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Biologie
Notizen:
Abstract To study the mechanism of spontaneous and UV-induced illegitimate recombination, we examined the formation of theλbio specialized transducing phage inEscherichia coli. Because mostλbio transducing phages have double defects in thered andgam genes and have the capacity to form a plaque on anE. coli P2 lysogen (Spi− phenotype), we selectedλbio transducing phage by their Spi− phenotype, rather than using thebio marker. We determined sequences of recombination junctions ofλbio transducing phages isolated with or without UV irradiation and deduced sequences of parental recombination sites. The recombination sites were widely distributed onE. coli bio andλ DNAs, except for a hotspot which accounts for 57% of UV-inducedλbio transducing phages and 77% of spontaneously inducedλbio transducing phages. The hotspot sites onE. coli andλ DNAs shared a short homology of 9 bp. In addition, we detected direct repeat sequences of 8 by within and near both thebio andλ hotspots. ArecA mutation did not affect the frequency of the recombination at the hotspot, indicating that this recombination is not a variant ofrecA-dependent homologous recombination. We discuss a model in which the short homology as well as the direct repeats play essential roles in illegitimate recombination at the hotspot.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF02191702
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