Alternate sigma factor RpoS is required for the in vivo-specific repression of Borrelia burgdorferi plasmid lp54-borne ospA and lp6.6 genes.
J Bacteriol
; 187(22): 7845-52, 2005 Nov.
Article
em En
| MEDLINE
| ID: mdl-16267308
ABSTRACT
While numerous positively regulated loci have been characterized during the enzootic cycle of Borrelia burgdorferi, very little is known about the mechanism(s) involved in the repression of borrelial loci either during tick feeding or within the mammalian host. Here, we report that the alternative sigma factor RpoS is required for the in vivo-specific repression of at least two RpoD-dependent B. burgdorferi loci, ospA and lp6.6. The downregulation of ospA and Ip6.6 appears to require either a repressor molecule whose expression is RpoS dependent or an accessory factor which enables RpoS to directly interact with the ospA and Ip6.6 promoter elements, thereby blocking transcription by RpoD. The central role for RpoS during the earliest stages of host adaptation suggests that tick feeding imparts signals to spirochetes that trigger the RpoS-dependent repression, as well as expression, of in vivo-specific virulence factors critical for the tick-to-mammalian host transition.
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Base de dados:
MEDLINE
Assunto principal:
Plasmídeos
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Fator sigma
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Proteínas da Membrana Bacteriana Externa
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Proteínas de Bactérias
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Regulação Bacteriana da Expressão Gênica
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Borrelia burgdorferi
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Lipoproteínas
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Antígenos de Superfície
Idioma:
En
Ano de publicação:
2005
Tipo de documento:
Article