SlrA/SinR/SlrR inhibits motility gene expression upstream of a hypersensitive and hysteretic switch at the level of σ(D) in Bacillus subtilis.
Mol Microbiol
; 83(6): 1210-28, 2012 Mar.
Article
em En
| MEDLINE
| ID: mdl-22329926
ABSTRACT
Exponentially growing Bacillus subtilis cultures are epigenetically differentiated into two subpopulations in which cells are either ON or OFF for σ(d) -dependent gene expression a pattern suggestive of bistability. The gene encoding σ(D) , sigD, is part of the 31-gene fla/che operon where its location at the 3' end, 25 kb away from the strong P(fla/che) promoter, determines its expression level relative to a threshold. Here we show that addition of a single extra copy of the slrA gene in the chromosome inhibited σ(d) -dependent gene expression. SlrA together with SinR and SlrR reduced sigD transcript by potentiating a distance-dependent decrease in fla/che operon transcript abundance that was not mediated by changes in expression from the P(fla/che) promoter. Consistent with acting upstream of σ(D) , SlrA/SinR/SlrR was bypassed by artificial ectopic expression of sigD and hysteretically maintained for 20 generations by engaging the sigD gene at the native locus. SlrA/SinR/SlrR was also bypassed by increasing fla/che transcription and resulted in a hypersensitive output in flagellin expression. Thus, flagellin gene expression demonstrated hypersensitivity and hysteresis and we conclude that σ(d) -dependent gene expression is bistable.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fator sigma
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Bacillus subtilis
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Proteínas de Bactérias
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Regulação para Baixo
Idioma:
En
Revista:
Mol Microbiol
Assunto da revista:
BIOLOGIA MOLECULAR
/
MICROBIOLOGIA
Ano de publicação:
2012
Tipo de documento:
Article
País de afiliação:
Estados Unidos