Protective Role for H-NS Protein in IS
            <i>1</i>
            Transposition

Rouquette, Claudine; Serre, Marie-Claude; Lane, David

doi:10.1128/jb.186.7.2091-2098.2004

Cited by 20 publications

(23 citation statements)

References 47 publications

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“…Thus, the timing of transposition of certain elements is at least partially correlated with the cell replication cycle. Other biochemical and genetic studies have identified host factors, such as integration host factor, histone-like nucleoid structuring protein, and Hu, as playing an important-but not essentialrole in transposition of many elements (30,41,51,52,55). Indeed, the observation that these nucleoid-associated proteins can influence both transposition and site-specific recombination reinforces the proposal that these proteins communicate cellular status to the recombination machinery (6,53).…”

mentioning

confidence: 53%

Genetic Evidence that GTP Is Required for Transposition of IS 903 and Tn 552 in Escherichia coli

et al. 2005

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Surprisingly little is known about the role of host factors in regulating transposition, despite the potentially deleterious rearrangements caused by the movement of transposons. An extensive mutant screen was therefore conducted to identify Escherichia coli host factors that regulate transposition. An E. coli mutant library was screened using a papillation assay that allows detection of IS903 transposition events by the formation of blue papillae on a colony. Several host mutants were identified that exhibited a unique papillation pattern: a predominant ring of papillae just inside the edge of the colony, implying that transposition was triggered within these cells based on their spatial location within the colony. These mutants were found to be in pur genes, whose products are involved in the purine biosynthetic pathway. The transposition ring phenotype was also observed with Tn552, but not Tn10, establishing that this was not unique to IS903 and that it was not an artifact of the assay. Further genetic analyses of purine biosynthetic mutants indicated that the ring of transposition was consistent with a GTP requirement for IS903 and Tn552 transposition. Together, our observations suggest that transposition occurs during late stages of colony growth and that transposition occurs inside the colony edge in response to both a gradient of exogenous purines across the colony and the developmental stage of the cells.Transposons are defined as distinct regions of DNA that have the ability to move from one genomic location to another, a process mediated by element-encoded transposases (8, 9). While the main focus of transposition research has been in determining the detailed mechanisms of transposition, relatively little attention has been paid to how transposition is regulated in vivo or the in vivo requirements for the process (35). Transposon movement can result in gene inactivation (by insertional inactivation or deletion) or activation (by creation or introduction of promoters upstream of genes). In addition, intramolecular transposition can result in extensive DNA rearrangements, including deletions, inversions, and duplications of chromosome segments; these events are thought to play an important role in facilitating genome evolution (7-9). As the consequences of transposition can be either dire or favorable for the host organism, it is intuitive that the host has the capability to regulate this process. There are multiple examples of how transposons regulate their own movement, but very little work has focused on the role played by the host in regulating transposition. To address this, we have generated an insertion mutant library of Escherichia coli, which we have used to screen for host genes involved in regulation of IS903 transposition (E. Twiss, A. Coros, N. Tavakoli, and K. M. Derbyshire, unpublished data).The first comprehensive genetic screen for host mutants affecting transposition was carried out in 1985; it revealed a role for dam methylation in decreasing the rate of IS10, IS903, and IS50 transposi...

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confidence: 53%

Genetic Evidence that GTP Is Required for Transposition of IS 903 and Tn 552 in Escherichia coli

et al. 2005

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“…H-NS is inhibitory in the Mu system as it enhances the activity of the Mu repressor, thereby helping to block the transcription of genes whose products are required for transposition (Falconi et al 1991). In IS1 transposition, H-NS promotes transposition as it affects the amount of transposase (InsAB protein) produced, either by aiding in InsAB translation or by protecting InsAB from proteolysis (Rouquette et al 2004). H-NS also promotes IS903 and Tn552 transposition, but it is not yet known how it acts in these systems (Swingle et al 2004).…”

Section: Impact Of H-ns On Other Transposition Systemsmentioning

confidence: 99%

“…Several members of the bacterial nucleoid-associated family of proteins, including integration host factor (IHF), HU, and histone-like nucleoid structuring protein (H-NS) have been shown to modulate selected transposition systems (Craigie et al 1985;Morisato and Kleckner 1987;Surette and Chaconas 1989;Signon and Kleckner 1995;Shiga et al 2001;Rouquette et al 2004). It is particularly intriguing that H-NS should act in this fashion, because one of its main roles is to facilitate adaptation to environmental stresses (Dorman 2004).…”

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confidence: 99%

“…The hns mutant strain was shown to accumulate a Tn10 excision intermediate, an observation that is consistent with H-NS acting directly on the transpososome as opposed to affecting transposase expression. In contrast, H-NS influences bacteriophage Mu and IS1 transposition by influencing gene expression and protein stability, respectively (Falconi et al 1991;Rouquette et al 2004).…”

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confidence: 99%

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The global regulator H-NS acts directly on the transpososome to promote Tn10 transposition

Wardle¹,

O'Carroll²,

Derbyshire³

et al. 2005

Genes Dev.

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The histone-like nucleoid structuring (H-NS) protein is a global transcriptional regulator that is known to regulate stress response pathways and virulence genes in bacteria. It has also been implicated in the regulation of bacterial transposition systems, including Tn10. We demonstrate here that H-NS promotes Tn10 transposition by binding directly to the transposition complex (or transpososome). We present evidence that, upon binding, H-NS induces the unfolding of the Tn10 transpososome and helps to maintain the transpososome in an unfolded state. This ensures that intermolecular (as opposed to self-destructive intramolecular) transposition events are favored. We present evidence that H-NS binding to the flanking donor DNA of the transpososome is the initiating event in the unfolding process. We propose that by recruiting H-NS as a modulator of transposition, Tn10 has evolved a means of sensing changes in host physiology, as the amount of H-NS in the cell, as well its activity, are responsive to changes in environmental conditions. Sensing of environmental changes through H-NS would allow transposition to occur when it is most opportune for both the transposon and the host.

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“…These kinds of regulators bind to sequence-specific degenerate DNA sites and control DNA replication, recombination, and even transcription (36,45,51,64,65,157,179). Therefore, they affect the expression of several operons and genes and, unlike most other global regulators, are not affected by metabolic regulators.…”

Section: Figmentioning

confidence: 99%

Metabolic Engineering in the -omics Era: Elucidating and Modulating Regulatory Networks

Vemuri

Aristidou²

2005

Microbiol Mol Biol Rev

115

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The importance of regulatory control in metabolic processes is widely acknowledged, and several enquiries (both local and global) are being made in understanding regulation at various levels of the metabolic hierarchy. The wealth of biological information has enabled identifying the individual components (genes, proteins, and metabolites) of a biological system, and we are now in a position to understand the interactions between these components. Since phenotype is the net result of these interactions, it is immensely important to elucidate them not only for an integrated understanding of physiology, but also for practical applications of using biological systems as cell factories. We present some of the recent “-omics” approaches that have expanded our understanding of regulation at the gene, protein, and metabolite level, followed by analysis of the impact of this progress on the advancement of metabolic engineering. Although this review is by no means exhaustive, we attempt to convey our ideology that combining global information from various levels of metabolic hierarchy is absolutely essential in understanding and subsequently predicting the relationship between changes in gene expression and the resulting phenotype. The ultimate aim of this review is to provide metabolic engineers with an overview of recent advances in complementary aspects of regulation at the gene, protein, and metabolite level and those involved in fundamental research with potential hurdles in the path to implementing their discoveries in practical applications

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Protective Role for H-NS Protein in IS 1 Transposition

Cited by 20 publications

References 47 publications

Genetic Evidence that GTP Is Required for Transposition of IS 903 and Tn 552 in Escherichia coli

Genetic Evidence that GTP Is Required for Transposition of IS 903 and Tn 552 in Escherichia coli

The global regulator H-NS acts directly on the transpososome to promote Tn10 transposition

Metabolic Engineering in the -omics Era: Elucidating and Modulating Regulatory Networks

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