f factor


Summary: A plasmid whose presence in the cell, either extrachromosomal or integrated into the BACTERIAL CHROMOSOME, determines the "sex" of the bacterium, host chromosome mobilization, transfer via conjugation (CONJUGATION, GENETIC) of genetic material, and the formation of SEX PILI.

Top Publications

  1. Lu J, Frost L. Mutations in the C-terminal region of TraM provide evidence for in vivo TraM-TraD interactions during F-plasmid conjugation. J Bacteriol. 2005;187:4767-73 pubmed
    ..This arrangement of functional domains could in part allow TraM to receive the mating signal generated by donor-recipient contact and transfer it to the relaxosome, thereby triggering DNA transfer. ..
  2. Arutyunov D, Frost L. F conjugation: back to the beginning. Plasmid. 2013;70:18-32 pubmed publisher
    ..This short review is a reminder of the progress made in those days that will hopefully kindle renewed interest in these subjects as we approach a complete understanding of the mechanism of conjugation. ..
  3. Stern J, Schildbach J. DNA recognition by F factor TraI36: highly sequence-specific binding of single-stranded DNA. Biochemistry. 2001;40:11586-95 pubmed
    The TraI protein has two essential roles in transfer of conjugative plasmid F Factor. As part of a complex of DNA-binding proteins, TraI introduces a site- and strand-specific nick at the plasmid origin of transfer (oriT), cutting the DNA ..
  4. Datta S, Larkin C, Schildbach J. Structural insights into single-stranded DNA binding and cleavage by F factor TraI. Structure. 2003;11:1369-79 pubmed
    ..The full positive charge on the Mg(2+) and the architecture of the active site suggest multiple roles for Mg(2+) in DNA cleavage...
  5. Lee M, Kosuk N, Bailey J, Traxler B, Manoil C. Analysis of F factor TraD membrane topology by use of gene fusions and trypsin-sensitive insertions. J Bacteriol. 1999;181:6108-13 pubmed
    ..Studies of the F factor TraD protein imply that the protein takes on a structure with two membrane-spanning sequences and amino and ..
  6. Beranek A, Zettl M, Lorenzoni K, Schauer A, Manhart M, Koraimann G. Thirty-eight C-terminal amino acids of the coupling protein TraD of the F-like conjugative resistance plasmid R1 are required and sufficient to confer binding to the substrate selector protein TraM. J Bacteriol. 2004;186:6999-7006 pubmed publisher
    ..We also observed that TraD encoded by the closely related F factor bound to TraM encoded by the R1 plasmid...
  7. Lu J, Wong J, Edwards R, Manchak J, Frost L, Glover J. Structural basis of specific TraD-TraM recognition during F plasmid-mediated bacterial conjugation. Mol Microbiol. 2008;70:89-99 pubmed publisher
  8. Hekman K, Guja K, Larkin C, Schildbach J. An intrastrand three-DNA-base interaction is a key specificity determinant of F transfer initiation and of F TraI relaxase DNA recognition and cleavage. Nucleic Acids Res. 2008;36:4565-72 pubmed publisher
    ..Oligonucleotide cleavage assay results suggest the essential function of the three-base interaction may be to position the scissile phosphate for cleavage, rather than to directly contribute to binding affinity. ..
  9. Penfold S, Simon J, Frost L. Regulation of the expression of the traM gene of the F sex factor of Escherichia coli. Mol Microbiol. 1996;20:549-58 pubmed
    ..Thus, a control circuit has been established whereby traM is negatively regulated by the FinOP fertility inhibition system through its repression of TraJ expression, which adversely affects transcription of the traY gene. ..

More Information


  1. Larkin C, Datta S, Harley M, Anderson B, Ebie A, Hargreaves V, et al. Inter- and intramolecular determinants of the specificity of single-stranded DNA binding and cleavage by the F factor relaxase. Structure. 2005;13:1533-44 pubmed publisher
    The TraI protein of conjugative plasmid F factor binds and cleaves a single-stranded region of the plasmid prior to transfer to a recipient...
  2. Stern J, Anderson B, Owens T, Schildbach J. Energetics of the sequence-specific binding of single-stranded DNA by the F factor relaxase domain. J Biol Chem. 2004;279:29155-9 pubmed
    ..TraI36, the relaxase domain of TraI from plasmid F factor, binds a single-stranded DNA (ssDNA) oligonucleotide containing an F factor sequence with high affinity and ..
  3. Niki H, Hiraga S. Subcellular distribution of actively partitioning F plasmid during the cell division cycle in E. coli. Cell. 1997;90:951-7 pubmed
    ..The sopABC system caused replicated plasmid molecules to be positioned and tethered at the cell quarter sites. ..
  4. Zhong Z, Helinski D, Toukdarian A. Plasmid host-range: restrictions to F replication in Pseudomonas. Plasmid. 2005;54:48-56 pubmed
    ..This, however, is not the only barrier to F replication, as mini-F derivatives with an alternative promoter for RepE expression do not replicate in P. putida and are not stably maintained in P. aeruginosa. ..
  5. Daehnel K, Harris R, Maddera L, Silverman P. Fluorescence assays for F-pili and their application. Microbiology. 2005;151:3541-8 pubmed
    ..With one exception (G53C), cysteines elsewhere in the F-pilin primary structure did not abolish filament formation, although some mutations differentially affected F-pilus functions. ..
  6. Di Laurenzio L, Frost L, Paranchych W. The TraM protein of the conjugative plasmid F binds to the origin of transfer of the F and ColE1 plasmids. Mol Microbiol. 1992;6:2951-9 pubmed
    ..The TraM protein was also found to bind to a sequence in the oriT region of the non-conjugative plasmid ColE1 that resembles the three binding sites in the F oriT region. ..
  7. Wang Y, Yu X, Silverman P, Harris R, Egelman E. The structure of F-pili. J Mol Biol. 2009;385:22-9 pubmed publisher
    ..This coexistence of two very different symmetries is similar to what has recently been reported for an archaeal Methanococcus maripaludis pili filament and an archaeal Sulfolobus shibatae flagellar filament. ..
  8. Porter R, Black S. The single-stranded-DNA-binding protein encoded by the Escherichia coli F factor can complement a deletion of the chromosomal ssb gene. J Bacteriol. 1991;173:2720-3 pubmed
    ..We have tested one of the plasmid-borne ssb genes, the ssf gene from the E. coli F factor, for its ability to complement total deletion of the chromosomal ssb gene for viability...
  9. Street L, Harley M, Stern J, Larkin C, Williams S, Miller D, et al. Subdomain organization and catalytic residues of the F factor TraI relaxase domain. Biochim Biophys Acta. 2003;1646:86-99 pubmed
    TraI from conjugative plasmid F factor is both a "relaxase" that sequence-specifically binds and cleaves single-stranded DNA (ssDNA) and a helicase that unwinds the plasmid during transfer...
  10. Adachi S, Hori K, Hiraga S. Subcellular positioning of F plasmid mediated by dynamic localization of SopA and SopB. J Mol Biol. 2006;356:850-63 pubmed publisher
    ..The plasmid incompatibility mediated by the Sop system might be explained clearly by this hypothesis...
  11. Lawley T, Klimke W, Gubbins M, Frost L. F factor conjugation is a true type IV secretion system. FEMS Microbiol Lett. 2003;224:1-15 pubmed
    ..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. ..
  12. Larkin C, Datta S, Nezami A, Dohm J, Schildbach J. Crystallization and preliminary X-ray characterization of the relaxase domain of F factor TraI. Acta Crystallogr D Biol Crystallogr. 2003;59:1514-6 pubmed
    ..TraI is the relaxase for the conjugative plasmid F factor. A 36 kDa N-terminal fragment of TraI possesses the single-stranded DNA-binding and cleavage activity of the ..
  13. Andrup L, Andersen K. A comparison of the kinetics of plasmid transfer in the conjugation systems encoded by the F plasmid from Escherichia coli and plasmid pCF10 from Enterococcus faecalis. Microbiology. 1999;145 ( Pt 8):2001-9 pubmed
    ..In these conjugation systems, the donors underwent a 'recovery period' between rounds of conjugative transfer and newly formed transconjugants required a period of about 40-80 min to mature into proficient donors. ..
  14. Haft R, Gachelet E, Nguyen T, Toussaint L, Chivian D, Traxler B. In vivo oligomerization of the F conjugative coupling protein TraD. J Bacteriol. 2007;189:6626-34 pubmed
    ..Our data also show that different regions of TraD play distinct roles in the oligomerization process. We postulate a model for in vivo oligomerization and discuss the probable participation of individual domains of TraD in each step. ..
  15. Bouet J, Rech J, Egloff S, Biek D, Lane D. Probing plasmid partition with centromere-based incompatibility. Mol Microbiol. 2005;55:511-25 pubmed
    ..The results indicate the importance of kinetic considerations and suggest that mini-F handcuffing promotes pairing of SopB-sopC complexes that can subsequently segregate as intact aggregates. ..
  16. Hatano T, Yamaichi Y, Niki H. Oscillating focus of SopA associated with filamentous structure guides partitioning of F plasmid. Mol Microbiol. 2007;64:1198-213 pubmed
    ..The focus associated with filamentous distribution of SopA was also observed in a cell without nucleoid. The SopA filament may guide the movement of the plasmid as a railway track and lead it to cell quarters. ..
  17. Ragonese H, Haisch D, Villareal E, Choi J, Matson S. The F plasmid-encoded TraM protein stimulates relaxosome-mediated cleavage at oriT through an interaction with TraI. Mol Microbiol. 2007;63:1173-84 pubmed
  18. Bouet J, Ah Seng Y, Benmeradi N, Lane D. Polymerization of SopA partition ATPase: regulation by DNA binding and SopB. Mol Microbiol. 2007;63:468-81 pubmed
    ..The results suggest that in vivo, SopB smothers DNA by spreading from sopC, allowing SopA-ATP polymerization which initiates plasmid displacement. We propose that SopB and nucleoid DNA regulate SopA polymerization and hence partition. ..
  19. Lu J, Zhao W, Frost L. Mutational analysis of TraM correlates oligomerization and DNA binding with autoregulation and conjugative DNA transfer. J Biol Chem. 2004;279:55324-33 pubmed
    ..These findings support the hypothesis that TraM functions as a "signaling" factor that triggers DNA transport during F conjugation. ..
  20. Clarke M, Maddera L, Harris R, Silverman P. F-pili dynamics by live-cell imaging. Proc Natl Acad Sci U S A. 2008;105:17978-81 pubmed publisher
    ..Additionally and unexpectedly, we infer that extension and retraction are accompanied by rotation about the long axis of the filament. ..
  21. Schumacher M, Piro K, Xu W. Insight into F plasmid DNA segregation revealed by structures of SopB and SopB-DNA complexes. Nucleic Acids Res. 2010;38:4514-26 pubmed publisher
    ..This DNA-linking function suggests a novel mechanism for in trans DNA spreading by SopB, explaining how it might mask DNA to prevent DNA-mediated inhibition of SopA polymerization. ..
  22. Harley M, Toptygin D, Troxler T, Schildbach J. R150A mutant of F TraI relaxase domain: reduced affinity and specificity for single-stranded DNA and altered fluorescence anisotropy of a bound labeled oligonucleotide. Biochemistry. 2002;41:6460-8 pubmed
    b>F factor TraI is a helicase and a single-stranded DNA nuclease ("relaxase") essential for conjugative DNA transfer. A TraI domain containing relaxase activity, TraI36, was generated previously...
  23. Ravin N, Rech J, Lane D. Mapping of functional domains in F plasmid partition proteins reveals a bipartite SopB-recognition domain in SopA. J Mol Biol. 2003;329:875-89 pubmed
    ..Evidence for the involvement of the SopA N terminus in autoinhibition of SopA function was obtained, revealing a possible new aspect of the role of SopB in SopA activation. ..
  24. Williams S, Schildbach J. Examination of an inverted repeat within the F factor origin of transfer: context dependence of F TraI relaxase DNA specificity. Nucleic Acids Res. 2006;34:426-35 pubmed
  25. Mulec J, Starcic M, Zgur Bertok D. F-like plasmid sequences in enteric bacteria of diverse origin, with implication of horizontal transfer and plasmid host range. Curr Microbiol. 2002;44:231-5 pubmed publisher
  26. Matson S, Sampson J, Byrd D. F plasmid conjugative DNA transfer: the TraI helicase activity is essential for DNA strand transfer. J Biol Chem. 2001;276:2372-9 pubmed
    ..Thus, both the transesterase and helicase activities of TraI are essential for DNA strand transfer. ..
  27. Skovgaard O, Olesen K, Wright A. The central lysine in the P-loop motif of the Escherichia coli DnaA protein is essential for initiating DNA replication from the chromosomal origin, oriC, and the F factor origin, oriS, but is dispensable for initiation from the P1 plasmid origin, or. Plasmid. 1998;40:91-9 pubmed
    ..No replication activity was detected for this mutant protein from oriC. The different responses of the oriR and oriC replicons to the K178T DnaA protein indicate that the role of DnaA is different in the two systems. ..
  28. Thompson R, Taylor L, Kelly K, Everett R, Willetts N. The F plasmid origin of transfer: DNA sequence of wild-type and mutant origins and location of origin-specific nicks. EMBO J. 1984;3:1175-80 pubmed
    ..These key nucleotides may lie in a recognition sequence for the oriT endonuclease, since mutations at these sites prevent nicking at oriT ...
  29. Nelson W, Howard M, Sherman J, Matson S. The traY gene product and integration host factor stimulate Escherichia coli DNA helicase I-catalyzed nicking at the F plasmid oriT. J Biol Chem. 1995;270:28374-80 pubmed
    ..These data, coupled with data presented in the accompanying report, suggest that TraYp and IHF bind independent of one another, forming a nucleo-protein complex with oriT that can be recognized and nicked by TraIp. ..
  30. Castaing J, Bouet J, Lane D. F plasmid partition depends on interaction of SopA with non-specific DNA. Mol Microbiol. 2008;70:1000-11 pubmed publisher
    ..The behaviour of this mutant indicates a causal link between interaction with the cell's non-specific DNA and promotion of the dynamic behaviour that ensures F plasmid partition. ..
  31. Haft R, Palacios G, Nguyen T, Mally M, Gachelet E, Zechner E, et al. General mutagenesis of F plasmid TraI reveals its role in conjugative regulation. J Bacteriol. 2006;188:6346-53 pubmed
    ..Our data indicate that the domain responsible for conjugative repression resides in the central region of TraI between the protein's catalytic domains. ..
  32. Murakami H, Kita K, Oya H, Anraku Y. Chromosomal location of the Escherichia coli cytochrome b556 gene, cybA. Mol Gen Genet. 1984;196:1-5 pubmed
    ..It seems to function as a physiological electron transferring cytochrome in place of cytochrome b556 in this mutant. ..
  33. Elton T, Holland S, Frost L, Hazes B. F-like type IV secretion systems encode proteins with thioredoxin folds that are putative DsbC homologues. J Bacteriol. 2005;187:8267-77 pubmed
    ..TraF(F) is essential for conjugation but appears to have a function other than disulfide bond chemistry. ..
  34. Helmstetter C, Thornton M, Zhou P, Bogan J, Leonard A, Grimwade J. Replication and segregation of a miniF plasmid during the division cycle of Escherichia coli. J Bacteriol. 1997;179:1393-9 pubmed
  35. Anthony K, Klimke W, Manchak J, Frost L. Comparison of proteins involved in pilus synthesis and mating pair stabilization from the related plasmids F and R100-1: insights into the mechanism of conjugation. J Bacteriol. 1999;181:5149-59 pubmed
    ..Our results indicate that the specificity in recipient cell recognition and entry exclusion are mediated by TraN and TraG, respectively, and not by the pilus...
  36. Firshein W, Kim P. Plasmid replication and partition in Escherichia coli: is the cell membrane the key?. Mol Microbiol. 1997;23:1-10 pubmed
    ..Such domains may be induced transiently or be present at all times during the cell cycle. ..
  37. Maneewannakul S, Kathir P, Ippen Ihler K. Characterization of the F plasmid mating aggregation gene traN and of a new F transfer region locus trbE. J Mol Biol. 1992;225:299-311 pubmed
    ..The mating efficiency and pilus-specific phage susceptibility of a trbE::kan insertion mutant suggested that trbE is not essential for F transfer from Escherichia coli K-12 under standard mating conditions...
  38. Nomura N, Masai H, Inuzuka M, Miyazaki C, Ohtsubo E, Itoh T, et al. Identification of eleven single-strand initiation sequences (ssi) for priming of DNA replication in the F, R6K, R100 and ColE2 plasmids. Gene. 1991;108:15-22 pubmed
    ..Sequence homology is detected among some members from both groups. The possible biological roles of the ssi are discussed. ..
  39. Ogura T, Niki H, Kano Y, Imamoto F, Hiraga S. Maintenance of plasmids in HU and IHF mutants of Escherichia coli. Mol Gen Genet. 1990;220:197-203 pubmed
    ..The mini-P1 plasmid was slightly unstable in the himA-hip mutant, whereas the mini-F plasmid was stable. ..
  40. Loh S, Skurray R, Celerier J, Bagdasarian M, Bailone A, Devoret R. Nucleotide sequence of the psiA (plasmid SOS inhibition) gene located on the leading region of plasmids F and R6-5. Nucleic Acids Res. 1990;18:4597 pubmed
  41. Jalajakumari M, Manning P. Nucleotide sequence of the traD region in the Escherichia coli F sex factor. Gene. 1989;81:195-202 pubmed
    ..The lack of a typical terminator following traD and ORF1 and the translational coupling provided by overlapping stop and start codons is consistent with this conclusion. ..
  42. Yoshioka Y, Ohtsubo H, Ohtsubo E. Repressor gene finO in plasmids R100 and F: constitutive transfer of plasmid F is caused by insertion of IS3 into F finO. J Bacteriol. 1987;169:619-23 pubmed
    ..1946), who discovered sexuality in bacteria, may have had an Escherichia coli K-12 strain harboring such an finO F factor, which facilitated the generation of recombinant progeny useful for genetic analysis of bacteria and established ..
  43. Niki H, Ichinose C, Ogura T, Mori H, Morita M, Hasegawa M, et al. Chromosomal genes essential for stable maintenance of the mini-F plasmid in Escherichia coli. J Bacteriol. 1988;170:5272-8 pubmed
    ..Large amounts of linear multimers of plasmid DNA accumulated in mutants of the fifth linkage group (hopE). None of the hop mutations in any linkage group affected the normal growth of cells. ..
  44. Cassan M, Boy E, Borne F, Patte J. Regulation of the lysine biosynthetic pathway in Escherichia coli K-12: isolation of a cis-dominant constitutive mutant for AK III synthesis. J Bacteriol. 1975;123:391-9 pubmed
    ..One of them is identified as a cis-dominant constitutive mutant for the synthesis of the lysine-sensitive asportokinase AK III (lysC gene). ..
  45. Dutreix M, B ckman A, C l rier J, Bagdasarian M, Sommer S, Bailone A, et al. Identification of psiB genes of plasmids F and R6-5. Molecular basis for psiB enhanced expression in plasmid R6-5. Nucleic Acids Res. 1988;16:10669-79 pubmed
  46. Wu J, Ippen Ihler K. Nucleotide sequence of traQ and adjacent loci in the Escherichia coli K-12 F-plasmid transfer operon. J Bacteriol. 1989;171:213-21 pubmed
    ..In vivo utilization of the artA promoter and translational start sites was also examined by testing expression of an artA-beta-galactosidase fusion protein. These results indicated that the artA gene is expressed from its own promoter. ..
  47. Raleigh E, Elbing K, Brent R. Selected topics from classical bacterial genetics. Curr Protoc Mol Biol. 2002;Chapter 1:Unit 1.4 pubmed publisher
    ..Topics include antibiotics, the LAC operon, the F factor, nonsense suppressors, genetic markers, genotype and phenotype, DNA restriction, modification and methylation and ..
  48. Cheng X, Wang W, Molineux I. F exclusion of bacteriophage T7 occurs at the cell membrane. Virology. 2004;326:340-52 pubmed publisher
    ..These data suggest that the primary event that triggers the exclusion process occurs at the cytoplasmic membrane and that FxsA sequesters PifA so that membrane damage is minimized...
  49. Dao Thi M, Charlier D, Loris R, Maes D, Messens J, Wyns L, et al. Intricate interactions within the ccd plasmid addiction system. J Biol Chem. 2002;277:3733-42 pubmed
    ..This (CcdA(2)CcdB(2))(n) complex has multiple DNA-binding sites and spirals around the 120-bp promoter region. ..
  50. Miele L, Strack B, Kruft V, Lanka E. Gene organization and nucleotide sequence of the primase region of IncP plasmids RP4 and R751. DNA Seq. 1991;2:145-62 pubmed
    ..The R751 traC3 gene contains a stretch of 507 bp which is unrelated to RP4 traC or any other RP4 Tra1 gene. ..
  51. Buxton R, Drury L. Identification of the dye gene product, mutational loss of which alters envelope protein composition and also affects sex factor F expression in Escherichia coli K-12. Mol Gen Genet. 1984;194:241-7 pubmed
    ..1983) that the dye (= sfrA ) gene product is necessary for F-factor expression because it is required for translocation of the F-factor TraJ protein to the outer membrane.(ABSTRACT TRUNCATED AT 250 WORDS) ..
  52. Murayama N, Shimizu H, Takiguchi S, Baba Y, Amino H, Horiuchi T, et al. Evidence for involvement of Escherichia coli genes pmbA, csrA and a previously unrecognized gene tldD, in the control of DNA gyrase by letD (ccdB) of sex factor F. J Mol Biol. 1996;256:483-502 pubmed
    ..tldD is a novel gene, but the tldE and zfiA genes proved to be the pmbA gene (production of Microcin B17) and the csrA gene (carbon storage regulator), respectively...
  53. Fultz P, Kwoh D, Kemper J. Salmonella typhimurium newD and Escherichia coli leuC genes code for a functional isopropylmalate isomerase in Salmonella typhimurium-Escherichia coli hybrids. J Bacteriol. 1979;137:1253-62 pubmed
    ..coli does not have genes analogous to the S. typhimurium supQ newD genes, of that, if present, activation of a newD is a rare event or is lethal to the cell. ..