Analysis of the sequence and gene products of the transfer region of the F sex factor.

Frost, Laura S.; Ippen‐Ihler, Karin; Skurray, Ronald A.

doi:10.1128/mmbr.58.2.162-210.1994

Cited by 288 publications

(284 citation statements)

References 193 publications

(422 reference statements)

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“…These proteins together with the relaxase bind multiple sites within OriT (summarized in ref. [50] and in Fig 2A, lower panel). In the OriT of the F plasmid (F OriT), there are two IHF-binding sites (IHF A and B), two TraY-binding sites (sbyA and sbyC), three TraM-binding sites (sbmA-C), and as mentioned above, two TraIloading sites on each side of nic.…”

Section: Accessory Proteinsmentioning

confidence: 77%

From conjugation to T4S systems in Gram‐negative bacteria: a mechanistic biology perspective

2019

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Conjugation is the process by which bacteria exchange genetic materials in a unidirectional manner from a donor cell to a recipient cell. The discovery of conjugation signalled the dawn of genetics and molecular biology. In Gram‐negative bacteria, the process of conjugation is mediated by a large membrane‐embedded machinery termed “conjugative type IV secretion (T4S) system”, a large injection nanomachine, which together with a DNA‐processing machinery termed “the relaxosome” and a large extracellular tube termed “pilus” orchestrates directional DNA transfer. Here, the focus is on past and latest research in the field of conjugation and T4S systems in Gram‐negative bacteria, with an emphasis on the various questions and debates that permeate the field from a mechanistic perspective.

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Section: Accessory Proteinsmentioning

confidence: 77%

From conjugation to T4S systems in Gram‐negative bacteria: a mechanistic biology perspective

2019

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“…in this overview, as it is likely that homologs are functionally equivalent. Based on work on the F factor, the T4SS proteins are organized according to three proposed functions : (1) pilin and pilin processing, (2) pilus tip formation and pilus extension and (3) mating pair stabilization [7] (Figs. 1 and 2; Table 1).…”

Section: F-like T4ss Componentsmentioning

confidence: 99%

F factor conjugation is a true type IV secretion system

Lawley

Klimke

Gubbins

et al. 2003

FEMS Microbiology Letters

384

430

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The F sex factor of Escherichia coli is a paradigm for bacterial conjugation and its transfer (tra) region represents a subset of the type IV secretion system (T4SS) family. The F tra region encodes eight of the 10 highly conserved (core) gene products of T4SS including TraAF (pilin), the TraBF, ‐KF (secretin‐like), ‐VF (lipoprotein) and TraCF (NTPase), ‐EF, ‐LF and TraGF (N‐terminal region) which correspond to TrbCP, ‐IP, ‐GP, ‐HP, ‐EP, ‐JP, DP and TrbLP, respectively, of the P‐type T4SS exemplified by the IncP plasmid RP4. F lacks homologs of TrbBP (NTPase) and TrbFP but contains a cluster of genes encoding proteins essential for F conjugation (TraFF, ‐HF, ‐UF, ‐WF, the C‐terminal region of TraGF, and TrbCF) that are hallmarks of F‐like T4SS. These extra genes have been implicated in phenotypes that are characteristic of F‐like systems including pilus retraction and mating pair stabilization. F‐like T4SS systems have been found on many conjugative plasmids and in genetic islands on bacterial chromosomes. Although few systems have been studied in detail, F‐like T4SS appear to be involved in the transfer of DNA only whereas P‐ and I‐type systems appear to transport protein or nucleoprotein complexes. This review examines the similarities and differences among the T4SS, especially F‐ and P‐like systems, and summarizes the properties of the F transfer region gene products.

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“…Kado, unpublished). To circumvent the lack of osa expression in A. tumefaciens, transcription of the osa gene was placed under the control of a constitutive promoter derived from a kanamycin/spectinomycin operon [3,24]. Immunoblot analysis of the subcellular components of A. tumefaciens cells, containing the constitutively expressed osa gene, clearly showed the presence of Osa protein that specifically localizes to the inner membrane fraction.…”

Section: Discussionmentioning

confidence: 99%

“…Previously, by comparative amino acid sequence homology studies, we found that there are relatively close homologies between the amino acid sequence of Osa and that of an IncP plasmid RPI protein involved in fertility inhibition of IncW plasmids such as pSa [3]. Conjugative transfer requires the close association of specific proteins and plasmid DNA to form a complex at the membrane [24,25]. Fertility inhibition may result either through the alteration of such complexes by a protein identified to inhibit plasmid conjugative transfer, or by plugging the postulated pore through which the donor DNA must pass into the recipient cell.…”

Section: Discussionmentioning

confidence: 99%

Osa protein encoded by plasmid pSa is located at the inner membrane but does not inhibit membrane association of VirB and VirD virulence proteins in Agrobacterium tumefaciens

Chen¹

1996

FEMS Microbiology Letters

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The osa gene of IncW plasmid pSa encodes a 21-kDa protein that completely abolishes the oncogenic activity encoded by virulence genes in Agrobacterium tumefaciens. osa is the last gene of a four-gene operon in pSa, the expression of which appears to be highly regulated since the Osa protein is absent when either pSa or the osa operon is present in the Agrobacterium cell. When the osa gene alone or together with upstream genes within the operon are expressed under the control of a constitutive promoter. Osa protein is produced, enabling us to determine its subcellular location. Immunoblot analyses located Osa protein at the inner membrane of both A. tumefaciens and Escherichia coli. Because Osa inhibits oncogenicity of A. tumefaciens, and because alterations of the products of the virB and virD genes affect oncogenicity, studies were conducted to determine if there are changes in their specific association with the membranes in the presence Osa. Immunoblot analyses of VirB2, VirB3, VirB4, VirB9, and VirD4 in the presence and absence of Osa revealed no differences between the two treatments in these Vir protein associations with the membranes. These results indicate that both virB and virD gene products are produced in the presence of Osa; that they appear unaffected in their association with the membranes; and that Osa is associated with the inner membrane, where VirB2, VirB4, and VirD4 proteins are also located.

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Analysis of the sequence and gene products of the transfer region of the F sex factor.

Cited by 288 publications

References 193 publications

From conjugation to T4S systems in Gram‐negative bacteria: a mechanistic biology perspective

From conjugation to T4S systems in Gram‐negative bacteria: a mechanistic biology perspective

F factor conjugation is a true type IV secretion system

Osa protein encoded by plasmid pSa is located at the inner membrane but does not inhibit membrane association of VirB and VirD virulence proteins in Agrobacterium tumefaciens

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