Silencing and reactivation of urease in Yersinia pestis is determined by one G residue at a specific position in the ureD gene.
Yersinia pestis, the plague agent, is a naturally nonureolytic microorganism, while all other Yersinia species display a potent urease activity. In this report we demonstrate that Y. pestis harbors a complete urease locus composed of three structural (ureABC) and four accessory (ureEFGD) genes. Absence of ureolytic activity is due to the presence of one additional G residue in a poly(G) stretch, which introduces a premature stop codon in ureD. The presence of the same additional G in eight other Y. pestis isolates indicates that this mutation is species specific. Spontaneous excision of the extra G occurs at a frequency of 10(-4) to 10(-5) and restores a ureolytic phenotype to Y. pestis. The virulence of two independent ureolytic clones of Y. pestis injected either intravenously, subcutaneously, or intragastrically did not differ from that of the parental strain in the mouse infection model. Coinfection experiments with an equal number of ureolytic and nonureolytic bacteria did not evidence any difference in the ability of the two variants to multiply in vivo and to cause a lethal infection. Altogether our results demonstrate that variation of one extra G residue in ureD determines the ureolytic activity of Y. pestis but does not affect its virulence for mice or its ability to multiply and disseminate.
Sebbane
F
F
Equipe Inserm E9919-Université JE2225, Département de Pathogenèse des Maladies Infectieuses et Parasitaires, Institut de Biologie de Lille, 59021 Lille, France.
Devalckenaere
A
A
Foulon
J
J
Carniel
E
E
Simonet
M
M
D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics*; D001483:Base Sequence; D002874:Chromosome Mapping; D004789:Enzyme Activation; D005260:Female; D051379:Mice; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D014158:Transcription, Genetic; D014510:Urease / Q000235:genetics* / Q000378:metabolism; D014774:Virulence; D015010:Yersinia pestis / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity
D001426:Bacterial Proteins; C086767:UreD protein, Bacteria; D014510:Urease