Spatial relationship of the Fis binding sites for Hin recombinational enhancer activity

Johnson, Reid C.; Glasgow, Anna C.

doi:10.1038/329462a0

Cited by 93 publications

(58 citation statements)

References 22 publications

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“…Fis also plays a very important role in several DNA inversion systems, enhancing the inversion rate up to 150-fold. In the Hin system, for example, Fis exerts its effect through a DNA enhancer element which has two Fis binding sites separated by 4.5 turns of the helix (15). This enhancer has also been found to function in a distanceand orientation-independent manner (15 (39).…”

Section: Discussionmentioning

confidence: 99%

“…In the Hin system, for example, Fis exerts its effect through a DNA enhancer element which has two Fis binding sites separated by 4.5 turns of the helix (15). This enhancer has also been found to function in a distanceand orientation-independent manner (15 (39). Second, using the lambda infection assay to measure transposition at different stages of bacterial growth, we found that the peak of Fis stimulation occurred during the late exponential to early stationary growth phase.…”

Section: Discussionmentioning

confidence: 99%

“…The drugs used were kanamycin (40 ,ug/ml), tetracycline (15 ,ug/ml), gentamicin (5 ,ug/ml), nalidixic acid (20 ,ug/ml), and ampicillin (100 ,ug/ml). (25).…”

Section: Methodsmentioning

confidence: 99%

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Fis plays a role in Tn5 and IS50 transposition

Weinreich

Reznikoff

1992

J Bacteriol

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The Fis (factor for inversion stimulation) protein of Escherichia coli was found to influence the frequency of transposon TnS and insertion sequence ISSO transposition. Fis stimulated both TnS 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 TnS 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.TnS is a composite prokaryotic transposon which was originally isolated from a Kiebsiella R-factor (3), although it functions in a wide variety of gram-negative bacteria. It is composed of two insertion sequence IS50 elements oriented as inverted repeats with respect to a unique region encoding resistance to several antibiotics (Fig. 1). In general, transposition requires four components: (i) the element-encoded protein(s), termed transposase(s), which catalyze the DNA strand transfer reactions; (ii) specific DNA sequences at the ends of the transposon which delimit the element; (iii) accessory host factors which stimulate the reaction, most probably by facilitating the formation of higher-order protein-nucleic acid complexes; and (iv) target DNA (see reference 6 for a general review of transposition). Most prokaryotic transposons transpose to various target DNA sites with little sequence specificity. So, although transposition does require specific sequences at the ends of the element, it does not require homology with transposon sequences at the target site. Transposition therefore represents a distinct class of DNA rearrangements from the site-specific recombination reactions, in which reciprocal DNA strand exchange occurs between two precisely defined and closely related DNA sites. We are interested both in studying the regulation of TnS transposition in Escherichia coli and also in analyzing the mechanism of transposition utilized by TnS.TnS transposition requires the element-encoded transposase (Tnp) (13,20) Fis (factor for inversion stimulation) is a small, heat-stable DNA-binding protein in E. coli which was originally discovered through its ability to stimulate several site-specific DNA inversion reactions (18,22). Fis binds to its target site as a 20-kDa dimer and induces a substantial bend (>900) in the DNA (38), a property which is probably important in its various functions. In addition to its role in the DNA inversion systems, Fis...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Fis plays a role in Tn5 and IS50 transposition

Weinreich

Reznikoff

1992

J Bacteriol

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“…1). Supercoil diffusion underpins many genetic processes including integration and excision (Gellert et al, 1976;Miller et al, 1981;Gellert and Nash, 1987), bacteriophage Mu transposition (Craigie and Mizuuchi, 1986), Tn3 and ␥␦-mediated site-specific resolution (Benjamin et al, 1985;Stark et al, 1989), site-specific inversion (Johnson et al, 1987;Heichman and Johnson, 1990;Kanaar et al, 1990) and doubtless many other processes that involve DNA loops (Adhya, 1989;Eismann and Muller-Hill, 1990;Lobell and Schleif, 1990;Matthews, 1992;Haykinson and Johnson, 1993).…”

Section: Introductionmentioning

confidence: 99%

Gyrase and Topo IV modulate chromosome domain size in vivo

Stączek

1998

Molecular Microbiology

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SummaryIn bacteria, DNA supercoil movement is restricted to subchromosomal regions or 'domains.' To elucidate the nature of domain boundaries, we analysed reaction kinetics for ␥␦ site-specific resolution in six chromosomal intervals ranging in size from 14 to 90 kb. In stationary cultures of Salmonella typhimurium, resolution kinetics were rapid for both short and long intervals, suggesting that random stationary barriers occur with a 30% probability at approximately 80 kb intervals along DNA. To test the biochemical nature of domain barriers, a genetic screen was used to look for mutants with small domains. Rare temperaturesensitive alleles of DNA gyrase and Topo IV (the two essential type II topoisomerases) had more supercoil barriers than wild-type strains in all growth states. The most severe gyrase mutants were found to have twice as many barriers in growing cells as wild type throughout a 90 kb interval of the chromosome. We propose that knots and tangles in duplex DNA restrain supercoil diffusion in living bacteria.

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“…In addition to Hin protein and the hixL and hixR sites, the inversion reaction requires a DNA recombinational enhancer site and two other cell proteins, Fis and HU (Johnson and Simon 1985;Johnson et al 1986). The Fis protein interacts directly with the enhancer, whereas the HU protein is thought to contribute to the efficiency of the recombination reaction by enhanced bending of the DNA (Bruist et al 1987a;Johnson et al 1987). All of these factors orchestrate the formation of a specific protein-DNA complex necessary for the breakage and rejoining of DNA at the hixL and hixR sites resulting in inversion (Bruist et al 1987b).…”

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confidence: 99%