Different Impacts of MucR Binding to the <i>babR</i> and <i>virB</i> Promoters on Gene Expression in <i>Brucella abortus</i> 2308
Giorgia Borriello,
Veronica Russo,
Rubina Paradiso,
Marita Georgia Riccardi,
Daniela Criscuolo,
Gaetano Verde,
Rosangela Marasco,
Paolo Vincenzo Pedone,
Giorgio Galiero,
Ilaria Baglivo
Affiliations
Giorgia Borriello
Experimental Zooprophylactic Institute of Southern Italy, via Salute, 2, 80055 Portici, Italy
Veronica Russo
Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania “Luigi Vanvitelli”, via Vivaldi—43, 81100 Caserta, Italy
Rubina Paradiso
Experimental Zooprophylactic Institute of Southern Italy, via Salute, 2, 80055 Portici, Italy
Marita Georgia Riccardi
Experimental Zooprophylactic Institute of Southern Italy, via Salute, 2, 80055 Portici, Italy
Daniela Criscuolo
Experimental Zooprophylactic Institute of Southern Italy, via Salute, 2, 80055 Portici, Italy
Gaetano Verde
Institute of Genetics and Biophysics (IGB) “Adriano Buzzati-Traverso”, Consiglio Nazionale delle Ricerche (CNR), 80134 Naples, Italy
Rosangela Marasco
Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania “Luigi Vanvitelli”, via Vivaldi—43, 81100 Caserta, Italy
Paolo Vincenzo Pedone
Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania “Luigi Vanvitelli”, via Vivaldi—43, 81100 Caserta, Italy
Giorgio Galiero
Experimental Zooprophylactic Institute of Southern Italy, via Salute, 2, 80055 Portici, Italy
Ilaria Baglivo
Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania “Luigi Vanvitelli”, via Vivaldi—43, 81100 Caserta, Italy
The protein MucR from Brucella abortus has been described as a transcriptional regulator of many virulence genes. It is a member of the Ros/MucR family comprising proteins that control the expression of genes important for the successful interaction of α-proteobacteria with their eukaryotic hosts. Despite clear evidence of the role of MucR in repressing virulence genes, no study has been carried out so far demonstrating the direct interaction of this protein with the promoter of its target gene babR encoding a LuxR-like regulator repressing virB genes. In this study, we show for the first time the ability of MucR to bind the promoter of babR in electrophoretic mobility shift assays demonstrating a direct role of MucR in repressing this gene. Furthermore, we demonstrate that MucR can bind the virB gene promoter. Analyses by RT-qPCR showed no significant differences in the expression level of virB genes in Brucella abortus CC092 lacking MucR compared to the wild-type Brucella abortus strain, indicating that MucR binding to the virB promoter has little impact on virB gene expression in B. abortus 2308. The MucR modality to bind the two promoters analyzed supports our previous hypothesis that this is a histone-like protein never found before in Brucella.
