Mode of replicon fusion mediated by the duplicated insertion sequence IS21 in Escherichia coli.

Details

Serval ID
serval:BIB_0B0DC7B679A9
Type
Article: article from journal or magazin.
Collection
Publications
Title
Mode of replicon fusion mediated by the duplicated insertion sequence IS21 in Escherichia coli.
Journal
Genetics
Author(s)
Reimmann C., Haas D.
ISSN
0016-6731 (Print)
ISSN-L
0016-6731
Publication state
Published
Issued date
1987
Volume
115
Number
4
Pages
619-625
Language
english
Abstract
The insertion sequence IS21 (2.1 kb) originating from the broad-host-range IncP plasmid R68 transposes infrequently; by contrast, the IS21 tandem repeat found on the derivative R68.45 is highly active in transpositional mobilization of other replicons in a variety of Gram-negative bacteria. The mobilized plasmids are joined to R68.45 by single IS21 copies in direct orientation. The formation of IS21 tandem duplications was observed in cointegrates between R68.45 and pBR325::IS21 and also in an RP1::IS21 plasmid derivative in which a segment located between two directly repeated copies of IS21 was deleted spontaneously. We speculate that IS21 tandem repeats can arise when the termini of two IS21 elements are specifically joined in a transposition or deletion event. A resistance gene flanked by two IS21 elements in direct orientation did not behave as a transposon. The omega fragment carrying transcription and translation stop signals was inserted into various sites of the IS21 tandem repeat; in this way it could be shown that the left IS21 element (which is next to the kanamycin resistance gene in R68.45) was 100 times more active in cointegrate formation than was the right-hand element. Cointegrates between the conjugative plasmid R751 and pBR325 derivatives carrying IS21 and IS21::omega in tandem contained a single IS21 at one replicon junction and a single IS21::omega at the other. In the IS21 duplications the inner IS21 ends were preferentially recognized (presumably by IS21 transposase), whereas the outer termini were not required for cointegrate formation. Based on these findings a conservative (simple) pathway of transposition is proposed for R68.45 and other plasmids with an IS21 tandem repeat.(ABSTRACT TRUNCATED AT 250 WORDS)
Keywords
Chromosome Deletion, DNA Replication, DNA Restriction Enzymes, DNA Transposable Elements, Escherichia coli/genetics, Genes, Bacterial, Plasmids, Repetitive Sequences, Nucleic Acid, Replicon
Pubmed
Web of science
Create date
24/01/2008 14:00
Last modification date
20/08/2019 12:32
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