A cryptic plasmid of Yersinia enterocolitica encodes a conjugative transfer system related to the regions of CloDF13 Mob and IncX Pil

Abstract

Yersinia enterocolitica 29930 (biotype 1A; O : 7,8), the producing strain of the phage-tail-like bacteriocin enterocoliticin, possesses a plasmid-encoded conjugative type IV transfer system. The genes of the conjugative system were found by screening of a cosmid library constructed from total DNA of strain 29930. The cosmid Cos100 consists of the vector SuperCos1 and an insert DNA of 40 303 bp derived from a cryptic plasmid of strain 29930. The conjugative transfer system consists of genes encoding a DNA transfer and replication system (Dtr) with close relationship to the mob region of the mobilizable plasmid CloDF13 and a gene cluster encoding a mating pair formation system (Mpf) closely related to the Mpf system of the IncX plasmid R6K. However, a gene encoding a homologue of TaxB, the coupling protein of the IncX system, is missing. The whole transfer region has a size of approximately 17 kb. The recombinant plasmid Cos100 was shown to be transferable between Escherichia coli and Yersinia with transfer frequencies up to 0·1 transconjugants per donor. Mutations generated by inserting a tetracycline cassette into putative tri genes yielded a transfer-deficient phenotype. Conjugative transfer of the cryptic plasmid could not be demonstrated in the original host Y. enterocolitica 29930. However, a kanamycin-resistance-conferring derivative of the plasmid was successfully introduced into E. coli K-12 by transformation and was shown to be self-transmissible. Furthermore, Southern blot hybridization and PCR experiments were carried out to elucidate the distribution of the conjugative transfer system in Yersinia. In total, six Y. enterocolitica biotype 1A strains harbouring closely related systems on endogenous plasmids were identified.

The mating pair formation system of conjugative plasmids—A versatile secretion machinery for transfer of proteins and DNA

“…Stable expression of VirB3 requires the presence of the Mpf components VirB4 and VirB6 (Hapfelmeier et al, 2000;Jones et al, 1994). Since VirB4 is also required for targeting of VirB3 to the outer membrane (Jones et al, 1994), it is likely that VirB3 and VirB4 retain a close interaction in the Mpf complex, a presumption supported by the fact that VirB3 and VirB4 are encoded by a single gene (TriC) in case of the Cos100 conjugation system (Strauch et al, 2003). A second interaction partner of VirB3 may be the pilus-associated protein VirB5, which has been detected to interact with VirB3 in a yeast two-hybrid screen, a result which was conWrmed by in vitro data (Shamaei-Tousi et al, 2004).…”

Cryptic plasmid pSKU146 from the wall-less plant pathogen Spiroplasma kunkelii encodes an adhesin and components of a type IV translocation-related conjugation system

“…The ORF4 product also exhibited similarity (26% identity over 125 residues) to the TriL protein (GenBank Accession No. CAD58576) encoded by a cryptic plasmid that encodes a conjugative transfer system in Yersinia enterocolitica Strauch et al, 2003). This degree of similarity raises the possibility that the proteins encoded by these ORFs are the result of horizontal gene transfer and may be involved in horizontal transfer of plasmid pSKU146.…”

Bdellovibrio bacteriovorusStrains Produce a Novel Major Outer Membrane Protein during Predacious Growth in the Periplasm of Prey Bacteria

“…In the case of strain HD100, the PCR that was performed using the primer pair 5Ј-GARGARGGYAAYTTCTTCTACG G-3Ј and 5Ј-CGTAAACTTCCATYTCTGGAGAC-3Ј yielded a product that was further analyzed by sequencing. To identify the complete sequence of the coding region, gene libraries of B. bacteriovorus HD100 and HD114 were created by insertion of genomic DNA fragments partially digested with Sau3a into a SuperCos1 vector and introduction of the vector into E. coli VCS257 (45). The sequences of additional primers for the creation of a hybridization probe for the screening of the two cosmid gene libraries were deduced.…”