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Published on: August 5, 2016
Breaking the silence-role of MucR as a virulence determinant in Brucella
Ian S Barton1, Connor B Cribb1, Beatriz Tartilán-Choya2
1Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA.
Abstract:
The Zn finger protein MucR is an H-NS-like protein that serves as a gene silencer and nucleoid-structuring protein in the α-proteobacteria. MucR is also an essential virulence determinant in Brucella, where it directly and indirectly controls the expression of many genes required for the virulence of these bacteria in their mammalian hosts, including those encoding the Type IV secretion system and its effectors, the autotransporter adhesins BtaE and BmaC, and the quorum sensing regulators VjbR and BabR. Experimental evidence suggests that one of the primary functions of the Brucella MucR is to ensure that virulence genes are only expressed when their corresponding gene products provide fitness benefits to these bacteria during their infectious lifecycle, and we propose that this function is central to the well-established role of MucR as a virulence determinant.
Insights
The gene silencer MucR (a nucleoid-structuring protein) is crucial for Brucella virulence. MucR ensures bacterial virulence genes are expressed only when beneficial for survival during infection.
Area of Science:
- Microbiology
- Bacterial pathogenesis
- Gene regulation
Background:
- MucR is an H-NS-like protein in α-proteobacteria, acting as a gene silencer and nucleoid-structuring protein.
- MucR is an essential virulence factor in Brucella, regulating genes vital for mammalian host infection.
Purpose of the Study:
- To investigate the role of Brucella MucR in controlling virulence gene expression.
- To elucidate the function of MucR in ensuring timely expression of virulence factors for bacterial fitness.
Main Methods:
- The study likely involved genetic manipulation of Brucella strains.
- Analysis of gene expression related to virulence factors, secretion systems, and regulatory pathways.
- Experimental validation of MucR's role in bacterial survival and virulence in host models.
Main Results:
- MucR directly and indirectly controls numerous Brucella virulence genes.
- Key regulated genes include Type IV secretion system components, autotransporter adhesins (BtaE, BmaC), and quorum sensing regulators (VjbR, BabR).
Conclusions:
- MucR functions to express virulence genes only when they provide a fitness advantage during the infectious lifecycle.
- This precise regulation of virulence gene expression is central to MucR's role as a key determinant of Brucella virulence.
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