Processing of plasmid DNA during bacterial conjugation.

Willetts, Neil; Wilkins, Brian M.

doi:10.1128/mmbr.48.1.24-41.1984

Cited by 211 publications

(103 citation statements)

References 130 publications

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“…Unwinding is highly processive, at least in vitro, and can generate tracts of single-stranded DNA of -30 kb/ binding event (Roman et al, 1992). During conjugation with Hfr donors a single-strand of Hfr DNA with a 5' leading end is transferred to the recipient, where it provides a template for lagging-strand synthesis (Willetts and Wilkins, 1984). Discontinuities in the lagging strand provide single-stranded regions for the initiation of recombination that could be quite extensive.…”

Section: Discussionmentioning

confidence: 99%

Branch migration of three-strand recombination intermediates by RecG, a possible pathway for securing exchanges initiated by 3′-tailed duplex DNA.

Whitby

Lloyd

1995

The EMBO Journal

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RecG protein is required for normal levels of recombination and DNA repair in Escherichia coli. This 76 kDa polypeptide is a junction‐specific DNA helicase that acts post‐synaptically to drive branch migration of Holliday junction intermediates made by RecA during the strand exchange stage of recombination. To gain further insight into the role of RecG, we studied its activity on three‐strand intermediates formed by RecA between circular single‐stranded and linear duplex DNAs. Once RecA is removed, RecG drives branch migration of these intermediates by a junction‐targeted activity that depends on hydrolysis of ATP. RuvAB has a similar activity. However, when RecG is added to a RecA strand exchange reaction it severely reduces the accumulation of joint molecule intermediates by driving branch migration of junctions in the reverse direction to that catalysed by RecA strand exchange. In comparison, RuvAB has little effect on the reaction. We discuss how reverse branch migration by RecG, which acts counter of the 5′‐‐>3′ polarity of RecA binding and strand exchange, could serve to promote or abort the early stages of recombination, depending on the orientation of the single DNA strand initiating the exchange relative to the adjacent duplex region.

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Section: Discussionmentioning

confidence: 99%

Branch migration of three-strand recombination intermediates by RecG, a possible pathway for securing exchanges initiated by 3′-tailed duplex DNA.

Whitby

Lloyd

1995

The EMBO Journal

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“…Our findings provide the first physical evidence that specific plasmid-encoded proteins are transferred from the donor to the recipient cell during conjugation. The sog polypeptides are unlikely to be unique in this regard and the hypothetical nicking-closing enzyme that acts at the oriT site may prove to be another example of this type of protein (Warren et al, 1978;Willetts and Wilkins, 1984). Identification of other donor cell proteins retained by recipients, and any recipient cell protein that might be retained by donors, should provide valuable insight into the cell-to-cell interactions that are fundamental to bacterial conjugation.…”

Section: Discussionmentioning

confidence: 99%

“…Incorporation of the 240-kd polypeptide, and thus primase activity, into a complex with the 180-kd polypeptide provides an elegant scheme for optimizing initiation of DNA synthesis on the transferred plasmid strand. Only a minority of groups of conjugative plasmids specify a DNA primase (Lanka and Barth, 1981;Willetts and Wilkins, 1984) and of these at least the primase encoded by IncP plasmids functions in conjugation analogously to sog primase (Merryweather et al, 1986). However, a wider range of transferable plasmids may encode an analogue of the 180-kd polypeptide.…”

Section: *Aimmentioning

confidence: 99%

“…This report describes the construction and properties of the mutant, including its ability to promote transfer of mobilizable (Mob+) plasmids. The latter contain their own origin of transfer (oriT) site but rely on a conjugative plasmid, such as ColIb, to establish a functional conjugation system (Willetts and Wilkins, 1984). The results indicate that the C-terminal region of sog polypeptides facilitates transfer of ColIb DNA from the donor to the recipient cell.…”

Section: Introductionmentioning

confidence: 99%

“…The nature of the bridge that supports DNA transfer is poorly defined but it is currently imagined to be a specific pore formed following localized fusion of cell envelopes (Frost et al, 1984;Panicker and Minkley, 1985). One of the best characterized enzymes that function in the conjugative processing of DNA is the DNA primase specified by IncIl plasmids, such as ColIb-P9 (Willetts and Wilkins, 1984).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Role of sog polypeptides specified by plasmid ColIb-P9 and their transfer between conjugating bacteria.

Merryweather¹,

Rees²,

Smith³

et al. 1986

The EMBO Journal

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The sog gene of the conjugative plasmid ColIb‐P9 specifies two sequence‐related polypeptides with the N‐terminal third of the larger product having DNA primase activity. To resolve the function of the C‐terminal portion of the polypeptides, we constructed a ColIb mutant containing a Tn5 insertion in the 3′ region of sog. The mutation truncated sog gene products without inactivating DNA primase and rendered the plasmid defective in conjugation. Tests for the presence of conjugative pili, for complementation by a sog+ recombinant, and for mobilization of small origin of transfer (oriT) recombinant plasmids indicated that the mutant ColIb allows conjugative aggregation of cells but it is defective in DNA transfer at some stage subsequent to its initiation at oriT. Physical evidence is given that normal sog polypeptides are among a group of proteins transferred selectively from the donor to the recipient cell by a conjugation‐specific process. No transfer of the mutant sog proteins was detected. It is proposed that the C‐terminal region of sog polypeptides facilitates transfer of single‐stranded ColIb DNA between conjugating cells following initiation of transfer at the oriT site, and that in this role the proteins are transmitted to the recipient cell.

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Gene Exchange in Biofilms

Wuertz

2003

Encyclopedia of Environmental Microbiology

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Processing of plasmid DNA during bacterial conjugation.

Cited by 211 publications

References 130 publications

Branch migration of three-strand recombination intermediates by RecG, a possible pathway for securing exchanges initiated by 3′-tailed duplex DNA.

Branch migration of three-strand recombination intermediates by RecG, a possible pathway for securing exchanges initiated by 3′-tailed duplex DNA.

Role of sog polypeptides specified by plasmid ColIb-P9 and their transfer between conjugating bacteria.

Gene Exchange in Biofilms

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