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Microscopy-based Assays for High-throughput Screening of Host Factors Involved in Brucella Infection of Hela Cells
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The effects of MucR on expression of type IV secretion system, quorum sensing system and stress responses in Brucella

Hao Dong1, Wenxiao Liu, Xiaowei Peng

  • 1Key Laboratory of Animal Epidemiology and Zoonosis of Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing 100193, PR China.

Veterinary Microbiology
|August 13, 2013
PubMed

Insights

MucR, a key regulator in Brucella, controls virulence and stress resistance. Its absence significantly impacts gene expression, affecting virulence factors like the type IV secretion system and quorum sensing, crucial for bacterial survival.

Area of Science:

  • Microbiology
  • Bacterial Pathogenesis
  • Transcriptional Regulation

Background:

  • MucR is a transcriptional regulator essential for virulence in bacterial pathogens like Brucella spp.
  • It plays a role in virulence in mice and macrophages, stress response resistance, and cell envelope modification.
  • Understanding MucR's function is critical for deciphering Brucella pathogenesis.

Purpose of the Study:

  • To investigate the molecular mechanisms underlying the attenuation of a mucR deleted mutant in Brucella.
  • To identify genes regulated by MucR using transcriptomic analysis.
  • To elucidate the role of MucR in Brucella virulence, stress tolerance, and persistence.

Main Methods:

  • RNA sequencing (RNA-seq) was performed on Brucella melitensis 16M and a mucR deleted mutant (16MΔmucR).
  • Differential gene expression analysis was conducted to identify genes affected by MucR deletion.
  • Experimental verification of gene functions related to stress tolerance was performed.

Main Results:

  • A total of 442 differentially expressed genes were identified in the 16MΔmucR mutant compared to the wild type.
  • 310 genes were upregulated, and 132 genes were downregulated in the absence of MucR.
  • Notably, genes involved in the type IV secretion system, quorum sensing, metabolism, cell wall biogenesis, and stress tolerance (acid, iron-limitation) were significantly affected.

Conclusions:

  • MucR regulates a broad range of genes critical for Brucella virulence and survival.
  • The attenuation of the mucR mutant is linked to the downregulation of essential virulence systems, including type IV secretion and quorum sensing.
  • MucR's role in stress tolerance contributes significantly to Brucella's persistence in host environments.
Keywords:
Brucella melitensisMucRRNA-seq

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