This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Carnoy, C. Articles by Simonet, M. Search for Related Content PubMed PubMed Citation Articles by Carnoy, C. Articles by Simonet, M.

 Previous Article  |  Next Article 

Journal of Bacteriology, August 2002, p. 4489-4499, Vol. 184, No. 16
0021-9193/02/$04.00+0     DOI: 10.1128/JB.184.16.4489-4499.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.

The Superantigen Gene ypm Is Located in an Unstable Chromosomal Locus of Yersinia pseudotuberculosis

Christophe Carnoy,^1,2* Stephanie Floquet,¹ Michael Marceau,¹ Florent Sebbane,¹ Stephanie Haentjens-Herwegh,³ Annie Devalckenaere,³ and Michel Simonet^1,3

Equipe Mixte Inserm E9919—Université JE 2225—Institut Pasteur de Lille, Institut de Biologie de Lille,¹ Faculté des Sciences Pharmaceutiques et Biologiques,² Laboratoire de Bactériologie-Hygiène, Centre Hospitalier Régional et Universitaire de Lille, Lille, France³

Received 15 February 2002/ Accepted 24 May 2002

Yersinia pseudotuberculosis produces YPM (Y. pseudotuberculosis-derived mitogen), a superantigenic toxin that exacerbates the virulence of the bacterium in vivo. To date, three alleles of the superantigen gene (ypmA, ypmB, and ypmC) have been described. These genes are not found in all Y. pseudotuberculosis strains and have a low GC content, suggesting their location on mobile genetic elements. To elucidate this question, the genetic environment of the superantigen-encoding genes was characterized and 11 open reading frames (ORFs) were defined. Sequence analysis revealed that the ypm genes were not associated with plasmids, phages, transposons, or pathogenicity islands and that the superantigen genes were always located in the chromosome between ORF3 and ORF4. Nonsuperantigenic strains exhibited the same genetic organization of the locus but lacked the ypm gene between ORF3 and ORF4. A new insertion sequence, designated IS1398, which displays features of the Tn3 family, was characterized downstream of the ypmA and ypmC genes. A 13.3-kb region containing the ypm genes was not found in the genome of Y. pestis (CO92 and KIM 5 strains). We experimentally induced deletion of the ypm gene from a superantigen-expressing Y. pseudotuberculosis: using the association of aph(3')-IIIa and sacB genes, we demonstrated that when these reporter genes were present in the ypm locus, deletion of these genes was about 250 times more frequent than when they were located in another region of the Y. pseudotuberculosis chromosome. These results indicate that unlike other superantigenic toxin genes, the Yersinia ypm genes are not associated with mobile genetic elements but are inserted in an unstable locus of the genome.

---

* Corresponding author. Mailing address: Département de Pathogenèse des Maladies Infectieuses, Institut de Biologie de Lille, 1 rue du Professeur Calmette, F-59021 Lille cedex, France. Phone: 33 (0)3 20 87 11 81. Fax: 33 (0)3 20 87 11 83. E-mail: christophe.carnoy{at}ibl.fr.

---

Journal of Bacteriology, August 2002, p. 4489-4499, Vol. 184, No. 16
0021-9193/02/$04.00+0     DOI: 10.1128/JB.184.16.4489-4499.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.

This article has been cited by other articles:

• Collyn, F., Fukushima, H., Carnoy, C., Simonet, M., Vincent, P. (2005). Linkage of the Horizontally Acquired ypm and pil Genes in Yersinia pseudotuberculosis. Infect. Immun. 73: 2556-2558 [Abstract] [Full Text]  
• Collyn, F., Billault, A., Mullet, C., Simonet, M., Marceau, M. (2004). YAPI, a New Yersinia pseudotuberculosis Pathogenicity Island. Infect. Immun. 72: 4784-4790 [Abstract] [Full Text]