Promoter architecture in the flagellar regulon of Bacillus subtilis: high-level expression of flagellin by the sigma D RNA polymerase requires an upstream promoter element.
Proc Natl Acad Sci U S A
; 92(7): 2582-6, 1995 Mar 28.
Article
em En
| MEDLINE
| ID: mdl-7708689
ABSTRACT
Flagellin is one of the most abundant proteins in motile bacteria, yet its expression requires a low abundance sigma factor (sigma 28). We show that transcription from the Bacillus subtilis flagellin promoter is stimulated 20-fold by an upstream A+T-rich region [upstream promoter (UP) element] both in vivo and in vitro. This UP element is contacted by sigma 28 holoenzyme bound at the flagellin promoter and binds the isolated alpha 2 subassembly of RNA polymerase. The UP element increases the affinity of RNA polymerase for the flagellin promoter and stimulates transcription when initiation is limited by the rate of RNA polymerase binding. Comparison with other promoters in the flagellar regulon reveals a bipartite architecture the -35 and -10 elements confer specificity for sigma 28, while promoter strength is determined largely by upstream DNA sequences.
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Base de dados:
MEDLINE
Assunto principal:
Fator sigma
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Bacillus subtilis
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RNA Polimerases Dirigidas por DNA
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Expressão Gênica
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Regiões Promotoras Genéticas
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Regulon
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Flagelina
Idioma:
En
Ano de publicação:
1995
Tipo de documento:
Article