Characterization of in vitro constructed IS30-flanked transposons.
In order to facilitate functional studies on the mobile genetic element IS30, a resident of the Escherichia coli chromosome, transposon structures with two copies of IS30 flanking the chloramphenicol-resistance gene cat were constructed in vitro. Transposons containing IS30 as direct repeats (Tn2700 and Tn2702) transpose from multicopy plasmids into the genome of phage P1-15, thus giving rise to special transduction for cat with frequencies between 10(-5) and 10(-8)/plaque-forming unit. In contrast, transposon structures with IS30 in inverted repeat (Tn2701 and Tn2703) showed no detectable (less than 10(-9] transposition activity in vivo. By restriction analysis, two insertion sites of Tn2700 and Tn2702 on the phage P1-15 genome were indistinguishable from those observed earlier with a single copy of the IS30 element. These two insertion sites were used several times independently by Tn2700 and Tn2702. This confirms the non-random target selection by the element and it indicates that transposition of Tn2700 and Tn2702 follows the same rules as that of IS30.
Stalder
R
R
Department of Microbiology, Biozentrum der Universität Basel, Switzerland.
Arber
W
W
D001435:Bacteriophages / Q000235:genetics; D003001:Cloning, Molecular; D004251:DNA Transposable Elements; D004274:DNA, Recombinant; D004926:Escherichia coli / Q000235:genetics; D010957:Plasmids; D015183:Restriction Mapping; D014161:Transduction, Genetic
D004251:DNA Transposable Elements; D004274:DNA, Recombinant