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A MarR-Type regulator directly activates transcription from the Brucella abortus virB promoter by sharing a redundant role with HutC
- Source :
- CONICET Digital (CONICET), Consejo Nacional de Investigaciones Científicas y Técnicas, instacron:CONICET
- Publication Year :
- 2012
- Publisher :
- American Society for Microbiology, 2012.
-
Abstract
- Type IV secretion systems (T4SS) are multiprotein structures that direct the translocation of specific molecules across the bacterial cell envelope. As in other bacteria, pathogenicity of the genus Brucella essentially depends on the integrity of the T4SS-encoding virB operon, whose expression is regulated by multiple transcription factors belonging to different families. Previously, we identified IHF and HutC, two direct regulators of the virB genes that were isolated from total protein extracts of Brucella. Here, we report the identification of MdrA, a third regulatory element that was isolated using the same screening procedure. This transcription factor, which belongs to the MarR-family of transcriptional regulators, binds at two different sites of the virB promoter and regulates expression in a growth phase-dependent manner. Like other members of the MarR family, specific ligands were able to dissociate MdrA from DNA in vitro. Determination of the MdrA-binding sites by DNase I footprinting and analyses of protein-DNA complexes by electrophoresis mobility shift assays (EMSAs) showed that MdrA competes with IHF and HutC for the binding to the promoter because their target DNA sequences overlap. Unlike IHF, both MdrA and HutC bound to the promoter without inducing bending of DNA. Moreover, the two latter transcription factors activated virB expression to similar extents, and in doing so, they are functionally redundant. Taken together, our results show that MdrA is a regulatory element that directly modulates the activity of the virB promoter and is probably involved in coordinating gene expression in response to specific environmental signals Fil: Sieira, Rodrigo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentina Fil: Arocena, Gastón Maximiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentina Fil: Zorreguieta, Ángeles. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina Fil: Comerci, Diego José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; Argentina Fil: Ugalde, Rodolfo Augusto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; Argentina
- Subjects :
- DNA, Bacterial
Transcription, Genetic
Virulence Factors
Operon
Otras Ciencias Biológicas
Response element
DNA Footprinting
Brucella abortus
DNA footprinting
Electrophoretic Mobility Shift Assay
Biology
Microbiology
Ciencias Biológicas
purl.org/becyt/ford/1 [https]
Molecular Genetic
Transcription (biology)
Electrophoretic mobility shift assay
Promoter Regions, Genetic
purl.org/becyt/ford/1.6 [https]
Molecular Biology
Transcription factor
Genetics
Regulation of gene expression
Binding Sites
Promoter
Transcriptional Factor
Articles
Gene Expression Regulation, Bacterial
Brucella
Virb
CIENCIAS NATURALES Y EXACTAS
Protein Binding
Transcription Factors
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Journal :
- CONICET Digital (CONICET), Consejo Nacional de Investigaciones Científicas y Técnicas, instacron:CONICET
- Accession number :
- edsair.doi.dedup.....e381f27a07559d5a44eb1f26f96b476c