title: Fis plays a role in Tn5 and IS50 transposition.
abstract: The Fis (factor for inversion stimulation) protein of Escherichia coli was found to influence the frequency of transposon Tn5 and insertion sequence IS50 transposition. Fis stimulated both Tn5 and IS50 transposition events and also inhibited IS50 transposition in Dam-bacteria. This influence was not due to regulation by Fis of the expression of the Tn5 transposition proteins. We localized, by DNase I footprinting, one Fis site overlapping the inside end of IS50 and give evidence to strongly suggest that when Fis binds to this site, IS50 transposition is inhibited. The Fis site at the inside end overlaps three Dam GATC sites, and Fis bound efficiently only to the unmethylated substrate. Using a mobility shift assay, we also identified another potential Fis site within IS50. Given the growth phase-dependent expression of Fis and its differential effect on Tn5 versus IS50 transposition in Dam-bacteria, we propose that the high levels of Fis present during exponential growth stimulate transposition events and might bias those events toward Tn5 and away from IS50 transposition.
authors.affiliation: Department of Biochemistry, University of Wisconsin-Madison 53706.
authors.forename: M D
authors.initials: MD
authors.lastname: Weinreich
authors.forename: W S
authors.initials: WS
authors.lastname: Reznikoff
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites; D002352:Carrier Proteins / Q000378:metabolism* / Q000494:pharmacology; D002453:Cell Cycle / Q000502:physiology; D004251:DNA Transposable Elements / Q000235:genetics*; D004269:DNA, Bacterial / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D035021:Factor For Inversion Stimulation Protein; D034982:Integration Host Factors; D008969:Molecular Sequence Data; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific) / Q000378:metabolism
chemical_list: D000225:Adenine; D002352:Carrier Proteins; D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D035021:Factor For Inversion Stimulation Protein; D034982:Integration Host Factors; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific); C440502:integration host factor, E coli; C000730567:6-methyladenine