title: lcrH, a gene necessary for virulence of Yersinia pestis and for the normal response of Y. pestis to ATP and calcium.
abstract: We are investigating the functions of the three proteins encoded by the V operon (lcrGVH) of the low-calcium response virulence plasmid pCD1 of Yersinia pestis KIM5. The purpose of this study was to define the role of the 18-kilodalton protein encoded by lcrH, the third gene of the V operon. Using marker exchange mutagenesis, we constructed a Y. pestis mutant that failed to express the LcrH protein. This LcrH- mutant was "ATP blind" in that it failed to show altered growth and V-antigen expression at 37 degrees C when 18 mM ATP was present. It also showed only a partial response to 2.5 mM Ca2+. The parental Y. pestis strain showed full growth yield at 37 degrees C and depressed expression of V antigen and of yop (yersinial pCD1-encoded outer membrane protein) genes in response to ATP or Ca2+. In contrast, the LcrH- mutant failed to grow at 37 degrees C in the presence of ATP and showed only limited growth when Ca2+ was present. V-antigen expression in the mutant was not depressed by ATP and only partially depressed by Ca2+. These findings show that LcrH is necessary for the normal response of Y. pestis to ATP and that LcrH contributes to Ca2+ responsiveness. The mutant also showed abnormal yopJ expression, indicating that LcrH also is necessary for normal yop regulation. The LcrH- mutant was avirulent in mice, probably because of its compromised growth at 37 degrees C. These findings indicate that the responses of Y. pestis to ATP and Ca2+ are distinct and that lcrH encodes a protein that is an important mediator of Ca2+ and ATP regulation of pCD1-encoded virulence determinant(s) in Y. pestis.
authors.affiliation: Department of Microbiology and Immunology, Chandler Medical Center, University of Kentucky, Lexington 40536.
authors.forename: S B
authors.initials: SB
authors.lastname: Price
authors.forename: S C
authors.initials: SC
authors.lastname: Straley
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology; D000942:Antigens, Bacterial / Q000235:genetics*; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D002118:Calcium / Q000494:pharmacology; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics; D004252:DNA Mutational Analysis; D015180:Electrophoresis, Gel, Two-Dimensional; D005786:Gene Expression Regulation; D005798:Genes, Bacterial; D005809:Genes, Regulator; D007526:Isoelectric Point; D008970:Molecular Weight; D009876:Operon; D015183:Restriction Mapping; D015010:Yersinia pestis / Q000235:genetics* / Q000254:growth & development / Q000472:pathogenicity
chemical_list: D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D000255:Adenosine Triphosphate; D015500:Chloramphenicol O-Acetyltransferase; D002118:Calcium