Cargando…

Probing key DNA contacts in AraR-mediated transcriptional repression of the Bacillus subtilis arabinose regulon

In the absence of arabinose, the AraR transcription factor represses the expression of genes involved in the utilization of arabinose, xylose and galactose in Bacillus subtilis. AraR exhibits a chimeric organization: the N-terminal DNA-binding region belongs to the GntR family and the C-terminal eff...

Descripción completa

Detalles Bibliográficos
Autores principales: Franco, Irina Saraiva, Mota, Luís Jaime, Soares, Cláudio Manuel, de Sá-Nogueira, Isabel
Formato: Texto
Lenguaje:English
Publicado: Oxford University Press 2007
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1950556/
https://www.ncbi.nlm.nih.gov/pubmed/17617643
http://dx.doi.org/10.1093/nar/gkm509
_version_ 1782134562771435520
author Franco, Irina Saraiva
Mota, Luís Jaime
Soares, Cláudio Manuel
de Sá-Nogueira, Isabel
author_facet Franco, Irina Saraiva
Mota, Luís Jaime
Soares, Cláudio Manuel
de Sá-Nogueira, Isabel
author_sort Franco, Irina Saraiva
collection PubMed
description In the absence of arabinose, the AraR transcription factor represses the expression of genes involved in the utilization of arabinose, xylose and galactose in Bacillus subtilis. AraR exhibits a chimeric organization: the N-terminal DNA-binding region belongs to the GntR family and the C-terminal effector-binding domain is homologous to the GalR/LacI family. Here, the AraR–DNA-binding interactions were characterized in vivo and in vitro. The effect of residue substitutions in the AraR N-terminal domain and of base-pair exchanges into an AraR–DNA-binding operator site were examined by assaying for AraR-mediated regulatory activity in vivo and DNA-binding activity in vitro. The results showed that residues K4, R45 and Q61, located in or near the winged-helix DNA-binding motif, were the most critical amino acids required for AraR function. In addition, the analysis of the various mutations in an AraR palindromic operator sequence indicated that bases G(9), A(11) and T(16) are crucial for AraR binding. Moreover, an AraR mutant M34T was isolated that partially suppressed the effect of mutations in the regulatory cis-elements. Together, these findings extend the knowledge on the nature of AraR nucleoprotein complexes and provide insight into the mechanism that underlies the mode of action of AraR and its orthologues.
format Text
id pubmed-1950556
institution National Center for Biotechnology Information
language English
publishDate 2007
publisher Oxford University Press
record_format MEDLINE/PubMed
spelling pubmed-19505562007-08-22 Probing key DNA contacts in AraR-mediated transcriptional repression of the Bacillus subtilis arabinose regulon Franco, Irina Saraiva Mota, Luís Jaime Soares, Cláudio Manuel de Sá-Nogueira, Isabel Nucleic Acids Res Molecular Biology In the absence of arabinose, the AraR transcription factor represses the expression of genes involved in the utilization of arabinose, xylose and galactose in Bacillus subtilis. AraR exhibits a chimeric organization: the N-terminal DNA-binding region belongs to the GntR family and the C-terminal effector-binding domain is homologous to the GalR/LacI family. Here, the AraR–DNA-binding interactions were characterized in vivo and in vitro. The effect of residue substitutions in the AraR N-terminal domain and of base-pair exchanges into an AraR–DNA-binding operator site were examined by assaying for AraR-mediated regulatory activity in vivo and DNA-binding activity in vitro. The results showed that residues K4, R45 and Q61, located in or near the winged-helix DNA-binding motif, were the most critical amino acids required for AraR function. In addition, the analysis of the various mutations in an AraR palindromic operator sequence indicated that bases G(9), A(11) and T(16) are crucial for AraR binding. Moreover, an AraR mutant M34T was isolated that partially suppressed the effect of mutations in the regulatory cis-elements. Together, these findings extend the knowledge on the nature of AraR nucleoprotein complexes and provide insight into the mechanism that underlies the mode of action of AraR and its orthologues. Oxford University Press 2007-07 2007-07-07 /pmc/articles/PMC1950556/ /pubmed/17617643 http://dx.doi.org/10.1093/nar/gkm509 Text en © 2007 The Author(s) http://creativecommons.org/licenses/by-nc/2.0/uk/ This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Molecular Biology
Franco, Irina Saraiva
Mota, Luís Jaime
Soares, Cláudio Manuel
de Sá-Nogueira, Isabel
Probing key DNA contacts in AraR-mediated transcriptional repression of the Bacillus subtilis arabinose regulon
title Probing key DNA contacts in AraR-mediated transcriptional repression of the Bacillus subtilis arabinose regulon
title_full Probing key DNA contacts in AraR-mediated transcriptional repression of the Bacillus subtilis arabinose regulon
title_fullStr Probing key DNA contacts in AraR-mediated transcriptional repression of the Bacillus subtilis arabinose regulon
title_full_unstemmed Probing key DNA contacts in AraR-mediated transcriptional repression of the Bacillus subtilis arabinose regulon
title_short Probing key DNA contacts in AraR-mediated transcriptional repression of the Bacillus subtilis arabinose regulon
title_sort probing key dna contacts in arar-mediated transcriptional repression of the bacillus subtilis arabinose regulon
topic Molecular Biology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1950556/
https://www.ncbi.nlm.nih.gov/pubmed/17617643
http://dx.doi.org/10.1093/nar/gkm509
work_keys_str_mv AT francoirinasaraiva probingkeydnacontactsinararmediatedtranscriptionalrepressionofthebacillussubtilisarabinoseregulon
AT motaluisjaime probingkeydnacontactsinararmediatedtranscriptionalrepressionofthebacillussubtilisarabinoseregulon
AT soaresclaudiomanuel probingkeydnacontactsinararmediatedtranscriptionalrepressionofthebacillussubtilisarabinoseregulon
AT desanogueiraisabel probingkeydnacontactsinararmediatedtranscriptionalrepressionofthebacillussubtilisarabinoseregulon