Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0043167 (pertussis)
 19,595 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Bordetella pertussis, the etiologic agent of whooping cough, causes disease by employing an array of virulence factors controlled by the BvgA-BvgS two-component signal transduction system. Regulation by this system has been extensively characterized in vitro, where bvg-activated genes are repressed in a process known as phenotypic modulation. Differential regulation of these genes by the response regulator BvgA results in promoters that are activated early, middle, or late after being released from modulation. However, the in vivo environmental signal and regulation pattern has not been described. In order to investigate BvgAS-mediated regulation of B. pertussis virulence factors in vivo using the mouse aerosol challenge model, we have adapted the recombinase-based in vivo technology (RIVET) system for use in B. pertussis. We have demonstrated that these strains show resolution during in vitro growth under non-modulating conditions. In addition, we have demonstrated that modulating strains by growth on media containing MgSO4 does not affect virulence in the mouse aerosol challenge model. We have therefore used the RIVET system to reveal the time-course of gene expression in vivo for selected B. pertussis virulence factors (cya, fha, prn and ptx). Our data indicate that this method can be effectively used to monitor and compare in vivo and in vitro gene expression in B. pertussis, and that temporal regulation patterns previously observed in vitro are mirrored in vivo.
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PMID:Demonstration of differential virulence gene promoter activation in vivo in Bordetella pertussis using RIVET. 1566 Oct 4

A method of monitoring the sequential events of IS481 transposition into the ctag site of bvg operon of Bordetella pertussis has been developed. Reproduction of virulent B. pertussis cells in vitro is accompanied by intrachromosomal site-specific IS481 transposition, which, in turn, results in inactivation of bvg operon of the causative agent and cell avirulent state. Avirulent bvg mutants of B. pertussis are incapable of intramolecular IS481 transposition. The frequency of the transposition increases when MgSO4 and nicotinic acid are present the culture medium. In the absence of these modulating factors. IS481 transposition along B. pertussis chromosome is inhibited but not arrested completely. Negative regulation of the bvg-repressed genes of B. pertussis seems to be a mechanism that controls bvg-dependent IS481 transposition.
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PMID:[Bvg-negative regulation of repeated sequence transferring in Bordetella pertussis cells]. 1639 46

The whooping cough agent Bordetella pertussis regulates the production of its virulence factors by the BvgA/S system. Phosphorylated BvgA activates the virulence-activated genes (vags) and represses the expression of the virulence-repressed genes (vrgs) via the activation of the bvgR gene. In modulating conditions, with MgSO4, the BvgA/S system is inactive, and the vrgs are expressed. Here, we show that the expression of almost all vrgs depends on RisA, another transcriptional regulator. We also show that some vags are surprisingly no longer modulated by MgSO4 in the risA(-) background. RisA also regulates the expression of other genes, including chemotaxis and flagellar operons, iron-regulated genes, and genes of unknown function, which may or may not be controlled by BvgA/S. We identified RisK as the likely cognate RisA kinase and found that it is important for expression of most, but not all RisA-regulated genes. This was confirmed using the phosphoablative RisAD(60)N and the phosphomimetic RisAD(60)E analogues. Thus the RisA regulon adds a new layer of complexity to B. pertussis virulence gene regulation.
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PMID:The multifaceted RisA regulon of Bordetella pertussis. 2762 Jun 73


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