Molecular analysis of the virulence locus of the Salmonella dublin plasmid pSDL2.
The virulence properties of various non-typhoid Salmonella serotypes depend on the presence of large plasmids 60-100 kb in size. We have shown previously that the virulence region on the 80 kb plasmid pSDL2 of Salmonella dublin Lane maps within a 14kb SalI fragment. In this report we show that an 8.2 kb region within this fragment is sufficient to express lethal disease in BALB/c mice. Sequence analysis of this segment revealed six sequential open reading frames designated vsdA-F, which encode putative proteins of 13-65kDa. Deletion analysis and location of Tn5-oriT inserts which abolish virulence suggest that vsdA, vsdC, vsdD and vsdE are essential for virulence expression. Downstream of vsdF we discovered a locus involved in stable plasmid maintenance. Deletion of that region resulted in plasmid multimerization and instability.
Krause
M
M
Department of Medicine, University of California, San Diego 92103.
Roudier
C
C
Fierer
J
J
Harwood
J
J
Guiney
D
D
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D004269:DNA, Bacterial; D005260:Female; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010957:Plasmids; D015183:Restriction Mapping; D012475:Salmonella / Q000235:genetics* / Q000472:pathogenicity; D016415:Sequence Alignment; D014774:Virulence / Q000235:genetics
D004269:DNA, Bacterial