Isolation and characterization of IS elements repeated in the bacterial chromosome.
Shigella sonnei contains repetitive sequences, including an insertion element IS1, which can be isolated as double-stranded DNA fragments by DNA denaturation and renaturation and by treatment with S1 nuclease. In this paper, we describe a method of cloning the IS1 fragments prepared by the S1 nuclease digestion technique into phage M13mp8 RFI DNA. Several clones contained IS1, usually with a few additional bases. We isolated and characterized five other repetitive sequences using this method. One sequence, 1264 base-pairs in length, had terminal inverted repeats and contained two open reading frames. This sequence, called IS600, showed about 44% sequence homology with IS3 and was repeated more than 20 times in the Sh. sonnei chromosome. Another sequence (named IS629, 1310 base-pairs in length), which was repeated six times, was found also to be related to IS3 and thus IS600. Two other sequences (named IS630 and IS640, 1159 and 1092 base-pairs in length, respectively), which were repeated approximately ten times, had characteristic terminal inverted repeats and contained a large open reading frame coding for a protein. The inverted repeat sequences of IS630 were similar to the sequence at one end of IS200, a Salmonella-specific IS element. The fifth sequence, repeated ten times in Sh. sonnei, had about 98% sequence homology with a portion of IS2. The method described here can be applied to the isolation of IS or iso-IS elements present in any other bacterial chromosome.
Matsutani
S
S
Institute of Applied Microbiology, University of Tokyo, Japan.
Ohtsubo
H
H
Maeda
Y
Y
Ohtsubo
E
E
D002876:Chromosomes, Bacterial; D003001:Cloning, Molecular; D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D012091:Repetitive Sequences, Nucleic Acid; D012763:Shigella flexneri / Q000235:genetics; D012764:Shigella sonnei / Q000235:genetics
D004251:DNA Transposable Elements; D004269:DNA, Bacterial