Interactions of Phage Mu Enhancer and Termini that Specify the Assembly of a Topologically Unique Interwrapped Transpososome

Yin, Zhiqi; Suzuki, Asaka; Lou, Zheng; Jayaram, Makkuni; Harshey, Rasika M.

doi:10.1016/j.jmb.2007.06.086

Cited by 17 publications

(25 citation statements)

References 44 publications

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“…2A). The Mu transpososome is built from six MuA subunits, whose assembly at the Mu ends is directed by an ordered interaction between att and enhancer sites (33,34). The two MuA subunits bound at the L and R termini are responsible for catalysis, each acting in trans to carry out successive cleavage and strand transfer through the DDE active sites (35)(36)(37).…”

Section: Model For Endonuclease Activity In the Context Of The Transpmentioning

confidence: 99%

DNA repair by the cryptic endonuclease activity of Mu transposase

Choi¹,

Harshey²

2010

Proc. Natl. Acad. Sci. U.S.A.

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Phage Mu transposes by two distinct pathways depending on the specific stage of its life cycle. A common θ strand transfer intermediate is resolved differentially in the two pathways. During lytic growth, the θ intermediate is resolved by replication of Mu initiated within the flanking target DNA; during integration of infecting Mu, it is resolved without replication, by removal and repair of DNA from a previous host that is still attached to the ends of the incoming Mu genome. We have discovered that the cryptic endonuclease activity reported for the isolated C-terminal domain of the transposase MuA [Wu Z, Chaconas G (1995) A novel DNA binding and nuclease activity in domain III of Mu transposase: Evidence for a catalytic region involved in donor cleavage. EMBO J 14:3835-3843], which is not observed in the full-length protein or in the assembled transpososome in vitro, is required in vivo for removal of the attached host DNA or "5′flap" after the infecting Mu genome has integrated into the E. coli chromosome. Efficient flap removal also requires the host protein ClpX, which is known to interact with the C-terminus of MuA to remodel the transpososome for replication. We hypothesize that ClpX constitutes part of a highly regulated mechanism that unmasks the cryptic nuclease activity of MuA specifically in the repair pathway.MuA transposase | Mu DNA transposition | ClpX | retroviral integration | post-integration repair

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Section: Model For Endonuclease Activity In the Context Of The Transpmentioning

confidence: 99%

DNA repair by the cryptic endonuclease activity of Mu transposase

Choi¹,

Harshey²

2010

Proc. Natl. Acad. Sci. U.S.A.

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“…On supercoiled DNA, E is critical for MuA-mediated synapsis of the L and R Mu ends, where an initial ER synapse captures L to form an LER synapse that has 5 supercoils trapped within it (Fig. 1B, left) (Pathania et al , 2002, Yin et al , 2007, Harshey & Jayaram, 2006). IHF plays an important role at the enhancer as well, introducing a bend between O1 and O2 to optimize LER interactions; HU does the same between L1 and L2 (Surette & Chaconas, 1989, Surette & Chaconas, 1992, Allison & Chaconas, 1992, Lavoie & Chaconas, 1993).…”

Section: Introductionmentioning

confidence: 99%

“…1B, right) (Chaconas & Harshey, 2002, Harshey & Jayaram, 2006, Montano et al , 2012). Topological studies suggest that the L3/R3 subunits depend on E for their continued association with the transpososome (Harshey & Jayaram, 2006, Yin et al, 2007). …”

Section: Introductionmentioning

confidence: 99%

Controlling DNA degradation from a distance: a new role for the Mu transposition enhancer

Choi

Saha

Jang

et al. 2014

Molecular Microbiology

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Summary Phage Mu is unique among transposable elements in employing a transposition enhancer. The enhancer DNA segment is the site where the transposase MuA binds and makes bridging interactions with the two Mu ends, interwrapping the ends with the enhancer in a complex topology essential for assembling a catalytically active transpososome. The enhancer is also the site at which regulatory proteins control divergent transcription of genes that determine the phage lysis-lysogeny decision. Here we report a third function for the enhancer - that of regulating degradation of extraneous DNA attached to both ends of infecting Mu. This DNA is protected from nucleases by a phage protein until Mu integrates into the host chromosome, after which it is rapidly degraded. We find that leftward transcription at the enhancer, expected to disrupt its topology within the transpososome, blocks degradation of this DNA. Disruption of the enhancer would lead to the loss or dislocation of two non-catalytic MuA subunits positioned in the transpososome by the enhancer. We provide several lines of support for this inference, and conclude that these subunits are important for activating degradation of the flanking DNA. This work also reveals a role for enhancer topology in phage development.

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“…These three sites are brought together in a very stable protein-DNA complex called the Mu transpososome [31][32][33][34][35]. Part of the Mu transposition pathway is shown in Figure 2 (from [36]). MuA proteins first bind to E and attR sites on the DNA, trapping two DNA crossings.…”

Section: Difference Topology and The Mu Transpososomementioning

confidence: 99%

Determining the topology of stable protein–DNA complexes

Darcy

Vázquez

2013

Biochemical Society Transactions

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Difference topology is an experimental technique that can be used to unveil the topological structure adopted by two or more DNA segments in a stable protein-DNA complex. Difference topology has also been used to detect intermediates in a reaction pathway and to investigate the role of DNA supercoiling. In the present article, we review difference topology as applied to the Mu transpososome. The tools discussed can be applied to any stable nucleoprotein complex.

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Interactions of Phage Mu Enhancer and Termini that Specify the Assembly of a Topologically Unique Interwrapped Transpososome

Cited by 17 publications

References 44 publications

DNA repair by the cryptic endonuclease activity of Mu transposase

DNA repair by the cryptic endonuclease activity of Mu transposase

Controlling DNA degradation from a distance: a new role for the Mu transposition enhancer

Determining the topology of stable protein–DNA complexes

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