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The growth phase-dependent regulation of the pilus locus genes by two-component system TCS08 in Streptococcus

Xin-Ming Song1, Wayne Connor, Karsten Hokamp

  • 1Vaccine and Infectious Disease Organization (VIDO), University of Saskatchewan, 120 Veterinary Road, Saskatoon, Saskatchewan, S7N 5E3 Canada. xinming.song@usask.ca

Microbial Pathogenesis
|November 6, 2008
PubMed

Insights

Streptococcus pneumoniae's TCS08 regulates pneumococcal pili, affecting bacterial adherence and invasion of lung and nasopharyngeal cells. This two-component system (TCS08) influences virulence in a growth-dependent manner.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Pathogenesis

Background:

  • The two-component system (TCS08) in Streptococcus pneumoniae is known to influence virulence and regulate phosphotransferase system (PTS) genes in avirulent strains.
  • Its specific role in pathogenic strains and the underlying virulence mechanisms remain largely uncharacterized.

Purpose of the Study:

  • To investigate the function of TCS08 in a pathogenic strain of Streptococcus pneumoniae (serotype 4, TIGR4).
  • To identify target genes regulated by TCS08 and elucidate its role in host cell interaction.

Main Methods:

  • Construction of TCS08 knockout mutants in the TIGR4 strain.
  • Transcriptional profile analysis to identify differentially expressed genes.
  • Quantitative real-time PCR (qRT-PCR) for gene expression validation.
  • Phenotype analyses measuring bacterial adherence and invasion of human lung (A549) and nasopharyngeal (Detroit 562) epithelial cells.

Main Results:

  • Disruption of TCS08 led to the up-regulation of pneumococcal pili genes (rlrA islet, SP0461-SP0468), particularly in late-logarithmic growth phases.
  • TCS08 knockout mutants exhibited increased adherence to A549 cells at late-logarithmic and stationary phases.
  • A significant reduction in the invasion of epithelial cells was observed in the TCS08 knockout mutants across different growth phases.

Conclusions:

  • TCS08 plays a crucial role in the virulence of pathogenic Streptococcus pneumoniae.
  • TCS08 regulates bacterial adherence and invasion of host epithelial cells, likely through modulation of pilus locus genes.
  • The function of TCS08 is dependent on the bacterial growth phase.

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