title: Isolation of E. coli mutants containing multiple transpositions of IS sequences.
abstract: The characterization of three E. coli mutants that appeared to have unselected IS1 insertions on the chromosome are described. One had a single new IS1 sequence. The second had three new IS1 sequences. The third had two new IS1 sequences and one of the IS1 sequences in the parent was missing. These mutants were found in a collection on strains that contained IS insertions in the spc operon. The frequency of finding mutants with unselected IS1 transpositions was at least 100 times greater than expected. The results suggest several transposition events may frequently occur in the same cell.
mesh_terms: D001483:Base Sequence; D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000235:genetics; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000235:genetics* / Q000302:isolation & purification; D009154:Mutation; D009876:Operon; D010641:Phenotype
chemical_list: D004251:DNA Transposable Elements; D004269:DNA, Bacterial