The Nucleoid Binding Protein H-NS Acts as an Anti-Channeling Factor to Favor Intermolecular Tn10 Transposition and Dissemination

Singh, Randeep; Liburd, Janine; Wardle, Simon J.; Haniford, David B.

doi:10.1016/j.jmb.2007.12.035

Cited by 18 publications

(20 citation statements)

References 44 publications

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“…In the equivalent reactions supplemented with H-NS, target-site channeling was reduced as evidenced by the reduction in the level of UKIC and an increase in the level of transposition products indicative of unconstrained target-site interactions, including intermolecular transposition events. Importantly, the antichanneling effect of H-NS was blocked by increasing the amount of IHF added to reactions, which is consistent with H-NS and IHF competing for binding sites within Tsomes (39). More generally, the capacity of H-NS to act as an antichanneling factor would be expected to increase the frequency of productive transposition events in the Tn10 system; this is consistent with the observation that the frequency of Tn10 transposition was reduced in strains of E. coli containing either an hns disruption or specific loss of function hns alleles, such as P116S (34).…”

Section: H-ns May Function In a Postexcision Capacity In Tn10 Transposupporting

confidence: 63%

Transposons Tn 10 and Tn 5

Haniford

Ellis

2015

Microbiol Spectr

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The study of the bacterial transposons Tn10 and Tn5 has provided a wealth of information regarding steps in nonreplicative DNA transposition, transpososome dynamics and structure, as well as mechanisms employed to regulate transposition. The focus of ongoing research on these transposons is mainly on host regulation and the use of the Tn10 antisense system as a platform to develop riboregulators for applications in synthetic biology. Over the past decade two new regulators of both Tn10 and Tn5 transposition have been identified, namely H-NS and Hfq proteins. These are both global regulators of gene expression in enteric bacteria with functions linked to stress-response pathways and virulence and potentially could link the Tn10 and Tn5 systems (and thus the transfer of antibiotic resistance genes) to environmental cues. Work summarized here is consistent with the H-NS protein working directly on transposition complexes to upregulate both Tn10 and Tn5 transposition. In contrast, evidence is discussed that is consistent with Hfq working at the level of transposase expression to downregulate both systems. With regard to Tn10 and synthetic biology, some recent work that incorporates the Tn10 antisense RNA into both transcriptional and translational riboswitches is summarized.

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Section: H-ns May Function In a Postexcision Capacity In Tn10 Transposupporting

confidence: 63%

Transposons Tn 10 and Tn 5

Haniford

Ellis

2015

Microbiol Spectr

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“…This suicidal transposition event is called autointegration, self-integration or intramolecular transposition, and is well characterized in prokaryotes [14]–[16]. The best-understood example in bacteria is Tn 10 transposition, in which regulation of transposition is a delicate interplay between the transposon and host-encoded factors [17]–[19]. These host factors, namely IHF (integration host factor), HU (heat unstable nucleoid protein) and H-NS (nucleoid structuring protein) are among the most important regulatory factors in E. coli .…”

Section: Introductionmentioning

confidence: 99%

Suicidal Autointegration of Sleeping Beauty and piggyBac Transposons in Eukaryotic Cells

Wang

Devaraj

et al. 2014

PLoS Genet

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Transposons are discrete segments of DNA that have the distinctive ability to move and replicate within genomes across the tree of life. ‘Cut and paste’ DNA transposition involves excision from a donor locus and reintegration into a new locus in the genome. We studied molecular events following the excision steps of two eukaryotic DNA transposons, Sleeping Beauty (SB) and piggyBac (PB) that are widely used for genome manipulation in vertebrate species. SB originates from fish and PB from insects; thus, by introducing these transposons to human cells we aimed to monitor the process of establishing a transposon-host relationship in a naïve cellular environment. Similarly to retroviruses, neither SB nor PB is capable of self-avoidance because a significant portion of the excised transposons integrated back into its own genome in a suicidal process called autointegration. Barrier-to-autointegration factor (BANF1), a cellular co-factor of certain retroviruses, inhibited transposon autointegration, and was detected in higher-order protein complexes containing the SB transposase. Increasing size sensitized transposition for autointegration, consistent with elevated vulnerability of larger transposons. Both SB and PB were affected similarly by the size of the transposon in three different assays: excision, autointegration and productive transposition. Prior to reintegration, SB is completely separated from the donor molecule and followed an unbiased autointegration pattern, not associated with local hopping. Self-disruptive autointegration occurred at similar frequency for both transposons, while aberrant, pseudo-transposition events were more frequently observed for PB.

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“…These host factors interact with specific sites near the transposon end and may help to initiate the reaction, or modulate the outcome, such as the choice of integration target site (Sewitz et al 2003;Crellin et al 2004;Liu et al 2005). In other cases, host factors such as the eukaryotic HMG and bacterial HU and H-NS proteins, may target distorted DNA structures near the transposon end (Chalmers et al 1998;Zayed et al 2003;Wardle et al 2005;Singh et al 2008;Whitfield et al 2009). These distortions probably arise from the skewed base composition and the repetition of simple sequence motifs at or near transposon ends.…”

Section: Internal Sequencesmentioning

confidence: 99%

Delivering the goods: viral and non-viral gene therapy systems and the inherent limits on cargo DNA and internal sequences

Atkinson

Chalmers

2010

Genetica

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Viruses have long been considered to be the most promising tools for human gene therapy. However, the initial enthusiasm for the use of viruses has been tarnished in the light of potentially fatal side effects. Transposons have a long history of use with bacteria in the laboratory and are now routinely applied to eukaryotic model organisms. Transposons show promise for applications in human genetic modification and should prove a useful addition to the gene therapy tool kit. Here we review the use of viruses and the limitations of current approaches to gene therapy, followed by a more detailed analysis of transposon length and the physical properties of internal sequences, which both affect transposition efficiency. As transposon length increases, transposition decreases: this phenomenon is known as length-dependence, and has implications for vector cargo capacity. Disruption of internal sequences, either via deletion of native DNA or insertion of exogenous DNA, may reduce or enhance genetic mobility. These effects may be related to host factor binding, essential spacer requirements or other influences yet to be elucidated. Length-dependence is a complex phenomenon driven not simply by the distance between the transposon ends, but by host proteins, the transposase and the properties of the DNA sequences encoded within the transposon.

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The Nucleoid Binding Protein H-NS Acts as an Anti-Channeling Factor to Favor Intermolecular Tn10 Transposition and Dissemination

Cited by 18 publications

References 44 publications

Transposons Tn 10 and Tn 5

Transposons Tn 10 and Tn 5

Suicidal Autointegration of Sleeping Beauty and piggyBac Transposons in Eukaryotic Cells

Delivering the goods: viral and non-viral gene therapy systems and the inherent limits on cargo DNA and internal sequences

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