Transcription activation by the siderophore sensor Btr is mediated by ligand-dependent stimulation of promoter clearance
| Autor: | Shawn R. MacLellan, Ahmed Gaballa, John D. Helmann |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2011 |
| Předmět: |
Transcriptional Activation
AraC Transcription Factor Siderophores Biology Bacillibactin Ligands DNA-binding protein 03 medical and health sciences chemistry.chemical_compound Bacterial Proteins Transcription (biology) Bacterial transcription RNA polymerase Genetics Binding site Promoter Regions Genetic Molecular Biology 030304 developmental biology Repetitive Sequences Nucleic Acid 0303 health sciences Binding Sites Models Genetic 030306 microbiology Activator (genetics) Promoter DNA-Directed RNA Polymerases Gene Expression Regulation Bacterial Molecular biology Cell biology DNA-Binding Proteins chemistry Mutation RNA Bacillus subtilis |
| Zdroj: | Nucleic Acids Research |
| ISSN: | 1362-4962 0305-1048 |
| Popis: | Bacterial transcription factors often function as DNA-binding proteins that selectively activate or repress promoters, although the biochemical mechanisms vary. In most well-understood examples, activators function by either increasing the affinity of RNA polymerase (RNAP) for the target promoter, or by increasing the isomerization of the initial closed complex to the open complex. We report that Bacillus subtilis Btr, a member of the AraC family of activators, functions principally as a liganddependent activator of promoter clearance. In the presence of its co-activator, the siderophore bacillibactin (BB), the Btr:BB complex enhances productive transcription, while having only modest effects on either RNAP promoter association or the production of abortive transcripts. Btr binds to two direct repeat sequences adjacent to the � 35 region; recognition of the downstream motif is most important for establishing a productive interaction between the Btr:BB complex and RNAP. The resulting Btr:BB dependent increase in transcription enables the production of the ferric-BB importer to be activated by the presence of its cognate substrate. |
| Databáze: | OpenAIRE |
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