The Rhizobium etli σ70 (SigA) factor recognizes a lax consensus promoter
| Autor: | Miguel A. Cevallos, Miguel A. Ramírez-Romero, Víctor González, Guillermo Dávila, Irina Masulis |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2006 |
| Předmět: |
DNA
Bacterial Transcriptional Activation Molecular Sequence Data Sequence alignment Sigma Factor Biology medicine.disease_cause Rhizobium etli Article Bacterial Proteins Sigma factor Consensus Sequence Genetics medicine Consensus sequence Promoter Regions Genetic Escherichia coli Reporter gene Binding Sites Bacteria Base Sequence Promoter DNA-Directed RNA Polymerases genomic DNA Mutagenesis Thermodynamics Transcription Initiation Site Sequence Alignment |
| Zdroj: | Nucleic Acids Research |
| ISSN: | 1362-4962 0305-1048 |
| Popis: | A collection of Rhizobium etli promoters was isolated from a genomic DNA library constructed in the promoter-trap vector pBBMCS53, by their ability to drive the expression of a gusA reporter gene. Thirty-seven clones were selected, and their transcriptional start-sites were determined. The upstream sequence of these 37 start-sites, and the sequences of seven previously identified promoters were compared. On the basis of sequence conservation and mutational analysis, a consensus sequence CTTGACN 16-23 TATNNT was obtained. In this consensus sequence, nine on of twelve bases are identical to the canonical Escherichia coli σ 70 promoter, however the R.etli promoters only contain 6.4 conserved bases on average. We show that the R.etli sigma factor SigA recognizes all R.etli promoters studied in this work, and that E.coli RpoD is incapable of recognizing them. The comparison of the predicted structure of SigA with the known structure of RpoD indicated that regions 2.4 and 4.2, responsible for promoter recognition, are different only by a single amino acid, whereas the region 1 of SigA contains 72 extra residues, suggesting that the differences contained in this region could be related to the lax promoter recognition of SigA. |
| Databáze: | OpenAIRE |
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