Genetic organization of the duplicated vap region of the Dichelobacter nodosus genome.
The recombinant plasmid pJIR318 contains a fragment of the Dichelobacter nodosus genome which is associated with virulence. Sequence analysis of the pJIR318 insert has shown that it contains four vap (virulence-associated protein) genes which are homologous to open reading frames found on the Escherichia coli F plasmid and the Neisseria gonorrhoeae cryptic plasmid (M. E. Katz, R. A. Strugnell, and J. I. Rood, Infect. and Immun. 60:4586-4592, 1992). The plasmid pJIR318 hybridizes to three regions of the D. nodosus genome, each of which has now been isolated. Regions 1 and 3 were found to be adjacent in the genome of D. nodosus A198, and the order of the vap genes in vap regions 1 and 2 were shown to be identical. Partial sequence analysis and Southern blot analysis of the vap regions showed that the three regions probably arose by a duplication event(s) followed by insertions and/or deletions. A recombinant plasmid, pJIR749, was isolated from a library of a benign D. nodosus strain, 305. This plasmid contained sequences from both ends of vap region 2. Analysis of pJIR749 showed that the sequences on either side of vap region 2 were separated by 324 bp in the genome of benign strain 305 and that the orientations of the sequences were different. It is clear that a simple insertion or deletion event did not generate the benign and virulent strains studied. A model which describes the evolution of the duplicated vap regions in D. nodosus A198 is presented.
Katz
M E
ME
Department of Animal Science, University of New England, Armidale, New South Wales, Australia.
Wright
C L
CL
Gartside
T S
TS
Cheetham
B F
BF
Doidge
C V
CV
Moses
E K
EK
Rood
J I
JI
D001421:Bacteria, Anaerobic / Q000235:genetics* / Q000472:pathogenicity*; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins; D005798:Genes, Bacterial / Q000235:genetics*; D016680:Genome, Bacterial; D008562:Membrane Glycoproteins / Q000235:genetics; D008969:Molecular Sequence Data; D005810:Multigene Family; D012689:Sequence Homology, Nucleic Acid; D014774:Virulence / Q000235:genetics; D037521:Virulence Factors
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D008562:Membrane Glycoproteins; D037521:Virulence Factors; C077520:VapD protein, Bacteria; C077518:VapC protein, Dichelobacter nodosus; C077517:VapB protein, Bacteria