Two different Escherichia coli proP promoters respond to osmotic and growth phase signals.
AUTOR(ES)
Mellies, J
RESUMO
proP of Escherichia coli encodes an active transport system for proline and glycine betaine which is activated by both hyperosmolarity and amino acid-limited growth. proP DNA sequences far upstream from the translational start site are strongly homologous to the promoter of proU, an operon that specifies another osmoregulated glycine betaine transport system. Mutation and deletion analysis of proP and primer extension experiments established that this promoter, P1, was responsible for proP's strong expression in minimal medium and its response to osmotic signals. When cells were grown in complex medium, expression from a proP-lacZ fusion was induced three- to fourfold as growth slowed and cells entered stationary phase. Stationary-phase induction was dependent on rpoS, which encodes a stationary-phase sigma factor. Deletion of 158 bp of the untranslated leader sequence between P1 and the proP structural gene abolished rpoS-dependent stationary-phase regulation. Transcription initiation detected by primer extension within this region was absent in an rpoS mutant. proP is therefore a member of the growing class of sigma S-dependent genes which respond to both stationary-phase and hyperosmolarity signals.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=176566Documentos Relacionados
- Protein ProQ Influences Osmotic Activation of Compatible Solute Transporter ProP in Escherichia coli K-12
- Fis activates the RpoS-dependent stationary-phase expression of proP in Escherichia coli.
- Cyclic AMP receptor protein functions as a repressor of the osmotically inducible promoter proP P1 in Escherichia coli.
- Growth phase-dependent induction of stationary-phase promoters of Escherichia coli in different gram-negative bacteria.
- Propriedades homologicas de grupos pro-p