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Transfer of the symbiotic plasmid of Rhizobium etli CFN42 requires cointegration with p42a, which may be mediated by site-specific recombination.
J Bacteriol. 2004 Nov; 186(22):7538-48.JB

Abstract

Plasmid p42a from Rhizobium etli CFN42 is self-transmissible and indispensable for conjugative transfer of the symbiotic plasmid (pSym). Most pSym transconjugants also inherit p42a. pSym transconjugants that lack p42a always contain recombinant pSyms, which we designated RpSyms*. RpSyms* do not contain some pSym segments and instead have p42a sequences, including the replication and transfer regions. These novel recombinant plasmids are compatible with wild-type pSym, incompatible with p42a, and self-transmissible. The symbiotic features of derivatives simultaneously containing a wild-type pSym and an RpSym* were analyzed. Structural analysis of 10 RpSyms* showed that 7 shared one of the two pSym-p42a junctions. Sequencing of this common junction revealed a 53-bp region that was 90% identical in pSym and p42a, including a 5-bp central region flanked by 9- to 11-bp inverted repeats reminiscent of bacterial and phage attachment sites. A gene encoding an integrase-like protein (intA) was localized downstream of the attachment site on p42a. Mutation or the absence of intA abolished pSym transfer from a recA mutant donor. Complementation with the wild-type intA gene restored transfer of pSym. We propose that pSym-p42a cointegration is required for pSym transfer; cointegration may be achieved either through homologous recombination among large reiterated sequences or through IntA-mediated site-specific recombination between the attachment sites. Cointegrates formed through the site-specific system but resolved through RecA-dependent recombination or vice versa generate RpSyms*. A site-specific recombination system for plasmid cointegration is a novel feature of these large plasmids and implies that there is unique regulation which affects the distribution of pSym in nature due to the role of the cointegrate in conjugative transfer.

Authors+Show Affiliations

Programa de Genética Molecular de Plásmidos Bacterianos, Centro de Investigación sobre Fijación de Nitrógeno, UNAM, Cuernavaca, Morelos, Mexico. sbrom@cifn.unam.mxNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15516565

Citation

Brom, Susana, et al. "Transfer of the Symbiotic Plasmid of Rhizobium Etli CFN42 Requires Cointegration With P42a, Which May Be Mediated By Site-specific Recombination." Journal of Bacteriology, vol. 186, no. 22, 2004, pp. 7538-48.
Brom S, Girard L, Tun-Garrido C, et al. Transfer of the symbiotic plasmid of Rhizobium etli CFN42 requires cointegration with p42a, which may be mediated by site-specific recombination. J Bacteriol. 2004;186(22):7538-48.
Brom, S., Girard, L., Tun-Garrido, C., García-de los Santos, A., Bustos, P., González, V., & Romero, D. (2004). Transfer of the symbiotic plasmid of Rhizobium etli CFN42 requires cointegration with p42a, which may be mediated by site-specific recombination. Journal of Bacteriology, 186(22), 7538-48.
Brom S, et al. Transfer of the Symbiotic Plasmid of Rhizobium Etli CFN42 Requires Cointegration With P42a, Which May Be Mediated By Site-specific Recombination. J Bacteriol. 2004;186(22):7538-48. PubMed PMID: 15516565.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Transfer of the symbiotic plasmid of Rhizobium etli CFN42 requires cointegration with p42a, which may be mediated by site-specific recombination. AU - Brom,Susana, AU - Girard,Lourdes, AU - Tun-Garrido,Cristina, AU - García-de los Santos,Alejandro, AU - Bustos,Patricia, AU - González,Víctor, AU - Romero,David, PY - 2004/11/2/pubmed PY - 2004/12/16/medline PY - 2004/11/2/entrez SP - 7538 EP - 48 JF - Journal of bacteriology JO - J. Bacteriol. VL - 186 IS - 22 N2 - Plasmid p42a from Rhizobium etli CFN42 is self-transmissible and indispensable for conjugative transfer of the symbiotic plasmid (pSym). Most pSym transconjugants also inherit p42a. pSym transconjugants that lack p42a always contain recombinant pSyms, which we designated RpSyms*. RpSyms* do not contain some pSym segments and instead have p42a sequences, including the replication and transfer regions. These novel recombinant plasmids are compatible with wild-type pSym, incompatible with p42a, and self-transmissible. The symbiotic features of derivatives simultaneously containing a wild-type pSym and an RpSym* were analyzed. Structural analysis of 10 RpSyms* showed that 7 shared one of the two pSym-p42a junctions. Sequencing of this common junction revealed a 53-bp region that was 90% identical in pSym and p42a, including a 5-bp central region flanked by 9- to 11-bp inverted repeats reminiscent of bacterial and phage attachment sites. A gene encoding an integrase-like protein (intA) was localized downstream of the attachment site on p42a. Mutation or the absence of intA abolished pSym transfer from a recA mutant donor. Complementation with the wild-type intA gene restored transfer of pSym. We propose that pSym-p42a cointegration is required for pSym transfer; cointegration may be achieved either through homologous recombination among large reiterated sequences or through IntA-mediated site-specific recombination between the attachment sites. Cointegrates formed through the site-specific system but resolved through RecA-dependent recombination or vice versa generate RpSyms*. A site-specific recombination system for plasmid cointegration is a novel feature of these large plasmids and implies that there is unique regulation which affects the distribution of pSym in nature due to the role of the cointegrate in conjugative transfer. SN - 0021-9193 UR - https://www.unboundmedicine.com/medline/citation/15516565/Transfer_of_the_symbiotic_plasmid_of_Rhizobium_etli_CFN42_requires_cointegration_with_p42a_which_may_be_mediated_by_site_specific_recombination_ L2 - http://jb.asm.org/cgi/pmidlookup?view=long&pmid=15516565 DB - PRIME DP - Unbound Medicine ER -