Complete DNA Sequence of Yersinia enterocolitica Serotype 0:8 Low-Calcium-Response Plasmid Reveals a New Virulence Plasmid-Associated Replicon

Abstract

The complete nucleotide sequence and organization of the Yersinia enterocolitica serotype 0:8 low-calciumresponse (LCR) plasmid, pYVe8081, were determined. The 67,720-bp plasmid encoded all the genes known to be part of the LCR stimulon except for ylpA. Eight of 13 intact open reading frames of unknown function identified in pYVe8081 had homologues in Yersinia pestis plasmid pCD1 or in Y. enterocolitica serotype 0:9 plasmid pYVe227. A region of approximately 17 kbp showed no DNA identity to pCD1 or pYVe227 and contained six potential new genes, a possible new replicon, and two intact insertion sequence (IS) elements. One intact IS element, ISYen1, was a new IS belonging to the IS256 family. Several vestigial IS elements appeared different from the IS distribution seen in the other LCR plasmids. The RepA proteins encoded by Y. enterocolitica serotype 0:8 pYVeWA and pYVe8081 were identical. The putative pYVe8081 replicon showed significant homology to the IncL/M replicon of pMU407.1 but was only distantly related to the replicons of pCD1 and pYVe227. In contrast, the putative partitioning genes of pYVe8081 showed 97% DNA identity to the spy/sopABC loci of pCD1 and pYVe227. Sequence analysis suggests that Yersinia LCR plasmids are from a common ancestor but that Y. enterocolitica serotype 0:8 plasmid replicons may have evolved independently via cointegrate formation following a transposition event. The change in replicon structure is predicted to change the incompatibility properties of Y. enterocolitica serotype 0:8 plasmids from those of Y. enterocolitica serotype 0:9 and Y. pestis LCR plasmids.Pathogenic Yersinia enterocolitica is a well-established foodborne pathogen (29). Infection usually results in a self-limiting gastroenteritis, but in immunocompromised individuals septicemia and hepatic abscesses may occur. Postinfection complications include arthritis and erythema nodosum (8). Y. enterocolitica is a serologically diverse species that includes saprophytes as well as pathogens. Certain serotypes are consistently associated with human infection (30). Serotypes 0:3 and 0:9 are most frequently isolated in Europe, Japan, and Canada, while serotype 0:8 causes most infections in the United States. Serotype 0:8 is also associated with more severe invasive disease (3, 5). So far, only one phenotypic trait has been identified in Y. enterocolitica 0:8 to account for these observed differences in pathogenicity (37).Essential virulence genes are carried on a ca.-70-kb plasmid in Y. enterocolitica, Yersinia pestis, and Yersinia pseudotuberculosis (42, 43). The virulence plasmid encodes virulence proteins called Yops (Yersinia outer proteins), a type III secretion system, the V antigen, and regulatory proteins. The virulence plasmid encodes the low-calcium response (LCR) (53), which refers to a complex response to in vitro growth conditions of temperature (37°C) and extracellular calcium concentration (less than 2.5 mM Ca 2ϩ ). Under these conditions, pathogenic Yersinia shifts from vegetative growth to the production a...

Evolutionary Dynamics of the Yersinia enterocolitica Complex

“…This difference has been noted before in hybridization experiments . The origin of replication of pYV8081 has been allocated to the IncL/M incompatibility group (Snellings, Popek and Lindler, 2001), and it has been noted that this is a feature of other pYVs from high-pathogenic BTs as well (Snellings, Popek and Lindler, 2001;Oberhettinger et al, 2011). Sequence similarity of the origin of replication in high-pathogenic pYVs to pYVs from low-pathogenic BTs is very low with 16% whereas protein identity is higher than 92% for the rest of the plasmid (Snellings, Popek and Lindler, 2001).…”

“…(Portnoy, Moseley and Falkow, 1981;Heesemann, et al, 1983;Portnoy, et al, 1984;Kapperud and Nesbakken, 1987;Fukushima, Gomyoda, Aleksic and Tsubokura, 1993). Variability was also shown in the sequence, orientation and position of some genes as well as gene content in general (Roggenkamp, et al, 1997;Boland, Havaux and Cornelis, 1998;Snellings, Popek and Lindler, 2001;Wagner, et al, 2009;Foultier and Cornelis, 2003;Oberhettinger, et al, 2011). The plasmids can consequently be considered as a "closely related family of plasmids" rather than a uniform molecule (Portnoy, Moseley and Falkow, 1981;.…”

“…The origin of replication of pYV8081 has been allocated to the IncL/M incompatibility group (Snellings, Popek and Lindler, 2001), and it has been noted that this is a feature of other pYVs from high-pathogenic BTs as well (Snellings, Popek and Lindler, 2001;Oberhettinger et al, 2011). Sequence similarity of the origin of replication in high-pathogenic pYVs to pYVs from low-pathogenic BTs is very low with 16% whereas protein identity is higher than 92% for the rest of the plasmid (Snellings, Popek and Lindler, 2001). Conversely, the origins of replication of both The arsenic resistance operon has been described as part of the transposon Tn2502 (Neyt, Iriarte, Thi and Cornelis, 1997 reported previously (Neyt, Iriarte, Thi and Cornelis, 1997).…”

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

“…A putative repA gene was identified whose product showed the closest relationship to the putative RepA protein of the virulence plasmid pYVe8081 of Y. enterocolitica strain 8081, which belongs to the pathogenic serotype O : 8 strains (Snellings et al, 2001). A number of replication initiation proteins of plasmids belonging to the I-complex also show significant similarities to the deduced RepA protein, which suggests that the cryptic plasmid of strain 29930, the source of Cos100 insert DNA, contains a replicon of this type.…”

“…The putative countertranscript RNA (RNAI)-encoding gene was easily identifiable by comparison with the corresponding sequences of the plasmids pYVe8081 (Snellings et al, 2001) and pSW800. The RNAI-encoding region stretches from nucleotide position 13330 to 13409 of the Cos100 insert DNA upstream from the start codon of the putatve repA and repB genes.…”