Iron starvation conditions upregulate Ehrlichia ruminantium type IV secretion system, tr1 transcription factor and map1 genes family through the master regulatory protein ErxR

Moumène Amal, Gonzalez-Rizzo Silvina, Lefrançois Thierry, Vachiéry Nathalie, Meyer Damien. 2018. Iron starvation conditions upregulate Ehrlichia ruminantium type IV secretion system, tr1 transcription factor and map1 genes family through the master regulatory protein ErxR. Frontiers in Cellular and Infection Microbiology, 7:535, 11 p.

Journal article ; Article de recherche ; Article de revue à facteur d'impact
Published version - Anglais
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Quartile : Q2, Sujet : MICROBIOLOGY / Quartile : Q2, Sujet : IMMUNOLOGY

Abstract : Ehrlichia ruminantium is an obligatory intracellular bacterium that causes heartwater, a fatal disease in ruminants. Due to its intracellular nature, E. ruminantium requires a set of specific virulence factors, such as the type IV secretion system (T4SS), and outer membrane proteins (Map proteins) in order to avoid and subvert the host's immune response. Several studies have been conducted to understand the regulation of the T4SS or outer membrane proteins, in Ehrlichia, but no integrated approach has been used to understand the regulation of Ehrlichia pathogenicity determinants in response to environmental cues. Iron is known to be a key nutrient for bacterial growth both in the environment and within hosts. In this study, we experimentally demonstrated the regulation of virB, map1, and tr1 genes by the newly identified master regulator ErxR (for Ehrlichia ruminantium expression regulator). We also analyzed the effect of iron depletion on the expression of erxR gene, tr1 transcription factor, T4SS and map1 genes clusters in E. ruminantium. We show that exposure of E. ruminantium to iron starvation induces erxR and subsequently tr1, virB, and map1 genes. Our results reveal tight co-regulation of T4SS and map1 genes via the ErxR regulatory protein at the transcriptional level, and, for the first time link map genes to the virulence function sensu stricto, thereby advancing our understanding of Ehrlichia's infection process. These results suggest that Ehrlichia is able to sense changes in iron concentrations in the environment and to regulate the expression of virulence factors accordingly.

Mots-clés Agrovoc : Ehrlichia ruminantium, Maladie bactérienne, Protéine bactérienne, Pouvoir pathogène, Fer, Transcription génique, Gène, Bovin

Mots-clés libres : Ehrlichia ruminantium, Type IV secretion system, Map1, Iron starvation, ErxR

Classification Agris : L73 - Animal diseases

Champ stratégique Cirad : Axe 4 (2014-2018) - Santé des animaux et des plantes

Agence(s) de financement européenne(s) : European Commission

Programme de financement européen : FP7

Projet(s) de financement européen(s) : One Health approach to integrate Guadeloupe research on vector-borne and emerging diseases in the ERA: from characterization of emergence mechanisms to innovative approaches for prediction and control

Auteurs et affiliations

  • Moumène Amal, Université de Montpellier (FRA)
  • Gonzalez-Rizzo Silvina, Université Paris-Sorbonne (FRA)
  • Lefrançois Thierry, CIRAD-DG-Saurs (FRA) ORCID: 0000-0001-8793-5228
  • Vachiéry Nathalie, CIRAD-BIOS-UMR ASTRE (FRA)
  • Meyer Damien, CIRAD-BIOS-UMR ASTRE (GLP) ORCID: 0000-0003-2735-176X - auteur correspondant

Source : Cirad-Agritrop (

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