Conjugation
From partsregistry.org
Bacterial conjugation is the transfer of genetic material between two bacterial cell via direct cell-to-cell contact. Although often incorrectly characterized as the bacterial equivalent of mating, in fact it is simply the transfer of genetic material from a donor cell to a recipient cell. Bacterial conjugation is also known as a "type IV secretion system".
This behaviour is characterized by the presence of a specialized plasmid (small, circular piece of transferrable DNA most often found within bacteria) known as a conjugative plasmid. The conjugative plasmid holds a distinct and specialized set of coding regions including the following
- OriT (Origin of Transfer): Unlike other plasmids, the conjugative plasmid has its own origin of transfer nic region. This is a specialized portion of the genome where one of the two strands of the circular plasmid DNA is cut to allow for rolling circle replication of the plasmid containing the OriT region into a recipient cell. During rolling circle replication, the cut end of one strand is inserted into the recipient cell while recipient polymerases construct the complementary strand back into a circular piece of DNA.
- TraJ (Transfer genes): The activation of this gene sets off a cascade of other plasmid genes (and thus corresponding protein expressions) which act in concert to form "mating" characteristics in the host bacterial cell. Such salient characteristics include:
- growth of a pilus--a long whip-like apparatus used to hook the two cells together
- fusion of the outer membranes to allow for transfer of genetic material
- formation of "surface exclusion proteins" which prevents the cell containing the conjugative plasmid from mating with other conjugative plasmids of its type
Two of the most well-studied and characterized types of conjugative plasmids are types "F" (from the F plasmid) and "R". The employed nomenclature for conjugative plasmid genes is the gene name first with the type afterwards. For example, the "TraJr" or "TraJR" gene denotes the "TraJ" gene of the "R" type conjugative plasmid.
Note it was previously believed that transfer of genetic material occurred via the pilus itself; now, most think that the transfer of genetic material occurs via a separate direct channel between the two cells.
| -?- | Name | Type | Description | Length | |
|---|---|---|---|---|---|
| BBa_I714000 | Conjugation | R388 oriT ( transfer origin of E.coli IncW group R388 plasmid) | 402 | ||
| BBa_I714003 | Conjugation | minimum oriT of plasmid R64 ( origin of transfer, R64 is IncI-1 ) | 83 | ||
1 | W | BBa_I714030 | Conjugation | OriT-F (Origin of Transfer for the F-plasmid nic region) | 355 |
| 1 | W | BBa_I714031 | Conjugation | OriT-R (Origin of Transfer for the R751-plasmid nic region) | 278 |
| A | W | BBa_I714032 | Conjugation | OriT-S (Origin of Transfer for the pSC101-plasmid nic region) | 131 |
| BBa_J01000 | Coding | TraJF controls conjugative transfer in F plasmid | 690 | ||
| 1 | BBa_J01001 | Coding | TraJr protein (controls conjugative transfer in RP4 plasmid) | 378 | |
| 1 | W | BBa_J01002 | Conjugation | OriT-F (Origin of Transfer for the F-plasmid nic region) | 365 |
| 1 | BBa_J01003 | Conjugation | OriT-R (Origin of transfer for the R-plasmid nic region) | 371 | |
| W | BBa_J01077 | Plasmid | F plasmid (x-OriT, x-TraJ) | ||
| W | BBa_J01078 | Plasmid | R plasmid (x-OriT, x-TraJ) | ||
| BBa_J23046 | Conjugation | put in later - SIL strain | |||
| A | W | BBa_J61030 | Composite | [OriTr][R6K] | 785 |
| A | BBa_K109550 | Coding | Bacterial conjugative regulator KorA | 306 | |
| A | BBa_K109551 | Coding | TrbA transcription factor for the Tra2 operon in incP alpha conjugation | 366 | |
| A | BBa_K125320 | Conjugation | OriT-RP4 (Origin of transfer for the RP4 plasmid) | 99 | |
| A | BBa_K125350 | Conjugation | oriTr with lac promoter and lacZ | 979 | |
| A | BBa_K125360 | Conjugation | oriT with lac promoter and lacZ | 707 | |
| A | W | BBa_K150006 | Conjugation | oriT | 471 |
| BBa_K175000 | Coding | trbC (pilin) of IncP beta R751 plasmid | 468 | ||
| S | W | BBa_K175001 | Coding | trbK (entry exclusion) of IncP beta R751 plasmid | 231 |
| BBa_K188777 | Conjugation | aka | 879 | ||
| BBa_K188778 | Conjugation | as | 856 | ||
| 
| Yifan Yang, Mingzhi Qu and the 2007 Peking Yniveristy iGEM team designed the parts BBa_I714000, BBa_I714003, BBa_I714030, BBa_I714031 and BBa_I714032. | 
| The 2005 Berkeley iGEM team designed the parts BBa_J01000-BBa_J01003 and BBa_J01077-BBa_J01078. | |
| Chris Anderson and the 2006 Berkeley iGEM team design the parts BBa_J23046. | 
| Ingrid Swanson and the 2008 University of Washington iGEM team designed the parts BBa_K109550 and BBa_K109551. | 
| Margaret Ruzicki and the 2008 University of Hawaii iGEM team designed the parts Part:BBa_K125320, Part:BBa_K125350, and Part:BBa_K125360. |
References
- Frost LS, Ippen-Ihler K, and Skurray RA. Analysis of the sequence and gene products of the transfer region of the F sex factor. Microbiol Rev 1994 Jun; 58(2) 162-210. pmid:7915817.
- Jaenecke S, de Lorenzo V, Timmis KN, and Díaz E. A stringently controlled expression system for analysing lateral gene transfer between bacteria. Mol Microbiol 1996 Jul; 21(2) 293-300. pmid:8858584.
- Lawley TD, Klimke WA, Gubbins MJ, and Frost LS. F factor conjugation is a true type IV secretion system. FEMS Microbiol Lett 2003 Jul 15; 224(1) 1-15. pmid:12855161.
- Lessl M, Balzer D, Weyrauch K, and Lanka E. The mating pair formation system of plasmid RP4 defined by RSF1010 mobilization and donor-specific phage propagation. J Bacteriol 1993 Oct; 175(20) 6415-25. pmid:8407818.
- Miller JF, Lanka E, and Malamy MH. F factor inhibition of conjugal transfer of broad-host-range plasmid RP4: requirement for the protein product of pif operon regulatory gene pifC. J Bacteriol 1985 Sep; 163(3) 1067-73. pmid:2993231.
- Martinez-Morales F, Borges AC, Martinez A, Shanmugam KT, and Ingram LO. Chromosomal integration of heterologous DNA in Escherichia coli with precise removal of markers and replicons used during construction. J Bacteriol 1999 Nov; 181(22) 7143-8. pmid:10559184.
- Wilkins BM. Plasmid promiscuity: meeting the challenge of DNA immigration control. Environ Microbiol 2002 Sep; 4(9) 495-500. pmid:12220405.
- Wikipedia entry on Bacterial Conjugation
- 2005 UC Berkeley iGEM team project and protocols
