title: [Study on the functions of potential new genes of Yersinia pestis type three secretion system].
abstract: OBJECTIVE
  To investigate the functional relations between the putative proteins YpCD1.08, YpCD1.09, YpCD1.16 encoded in pCD1 plasmid of Yersinia pestis and its type III secretion system (T3SS).
  
  
  METHODS
  Mutants of YpCD1.08, YpCD1.09, YpCD1.16 were constructed using λ-Red recombinant system. The growth curves of the mutant strains cultivated in TMH medium with or without calcium at 26 °C and 37 °C were determined to analyze the low calcium response phenotype. The transcription levels of ΔYpCD1.08, ΔYpCD1.09, ΔYpCD1.16 in Yersinia pestis and the dependence to temperature were determined using real time RT-PCR after cultivation at 26 °C and 37 °C and extraction of RNA. A β-lactamases reporter system was adopted to study the influence of these genes on the translocation of effector YopE of T3SS.
  
  
  RESULTS
  When grown in TMH medium without calcium at 26 °C and 37 °C, the growth curve of the YpCD1.08, YpCD1.09, YpCD1.16 mutants were similar to that of the wild-type strain, indicating that the low calcium response of all the mutants were normal. The ratios of YpCD1.08, YpCD1.09, YpCD1.16 gene transcriptional level at 37 °C and 26 °C were 2.3 ± 0.3, 2.3 ± 0.5 and 3.2 ± 0.7, respectively, indicating that these genes were transcribed in Yersinia pestis and their transcription regulations showed a temperature-dependence that was consistent with the well established temperature-dependent expression of Yersinia T3SS genes. The β-lactamases reporter assays demonstrated that ΔYpCD1.08 could translocate much higher level of YopE into HeLa cells, since that the light intensity ratio of 477/520 nm at 140 min was 2.5, whereas it was 1.8 for the wild-type strain, and the values in ΔYpCD1.09 and ΔYpCD1.16 were similar to the wild-type strain.
  
  
  CONCLUSIONS
  YpCD1.08, YpCD1.09, YpCD1.16 gene are likely to be the new members of T3SS, and the putative protein YpCD1.08 could play some roles in YopE secretion and translocation.
authors.affiliation: Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University College of Veterinary Medicine,Ya'an 625014, China.
authors.forename: Ting-ting
authors.initials: TT
authors.lastname: Zhang
authors.forename: Guang-neng
authors.initials: GN
authors.lastname: Peng
authors.forename: Hui-ying
authors.initials: HY
authors.lastname: Yang
authors.forename: Ya-fang
authors.initials: YF
authors.lastname: Tan
authors.forename: Ming-quan
authors.initials: MQ
authors.lastname: Cui
authors.forename: Na
authors.initials: N
authors.lastname: Wei
authors.forename: Wei
authors.initials: W
authors.lastname: Han
authors.forename: Zong-min
authors.initials: ZM
authors.lastname: DU
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism*; D058947:Bacterial Secretion Systems / Q000235:genetics*; D005798:Genes, Bacterial; D010957:Plasmids; D025941:Protein Interaction Mapping; D015010:Yersinia pestis / Q000235:genetics* / Q000378:metabolism* / Q000472:pathogenicity
chemical_list: D001425:Bacterial Outer Membrane Proteins; D058947:Bacterial Secretion Systems