UDP-glucose is a potential intracellular signal molecule in the control of expression of sigma S and sigma S-dependent genes in Escherichia coli.
AUTOR(ES)
Böhringer, J
RESUMO
The sigma S subunit of RNA polymerase is the master regulator of a regulatory network that controls stationary-phase induction as well as osmotic regulation of many genes in Escherichia coli. In an attempt to identify additional regulatory components in this network, we have isolated Tn10 insertion mutations that in trans alter the expression of osmY and other sigma S-dependent genes. One of these mutations conferred glucose sensitivity and was localized in pgi (encoding phosphoglucose isomerase). pgi::Tn10 strains exhibit increased basal levels of expression of osmY and otsBA in exponentially growing cells and reduced osmotic inducibility of these genes. A similar phenotype was also observed for pgm and galU mutants, which are deficient in phosphoglucomutase and UDP-glucose pyrophosphorylase, respectively. This indicates that the observed effects on gene expression are related to the lack of UDP-glucose (or a derivative thereof), which is common to all three mutants. Mutants deficient in UDP-galactose epimerase (galE mutants) and trehalose-6-phosphate synthase (otsA mutants) do not exhibit such an effect on gene expression, and an mdoA mutant that is deficient in the first step of the synthesis of membrane-derived oligosaccharides, shows only a partial increase in the expression of osmY. We therefore propose that the cellular content of UDP-glucose serves as an internal signal that controls expression of osmY and other sigma S-dependent genes. In addition, we demonstrate that pgi, pgm, and galU mutants contain increased levels of sigma S during steady-state growth, indicating that UDP-glucose interferes with the expression of sigma S itself.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=176605Documentos Relacionados
- Role for the histone-like protein H-NS in growth phase-dependent and osmotic regulation of sigma S and many sigma S-dependent genes in Escherichia coli.
- Sigma s-dependent promoters in Escherichia coli are located in DNA regions with intrinsic curvature.
- Impact of Heterologous Expression of Escherichia coli UDP-Glucose Pyrophosphorylase on Trehalose and Glycogen Synthesis in Corynebacterium glutamicum
- Transmembrane modulator-dependent bacterial tyrosine kinase activates UDP-glucose dehydrogenases
- Cloning and endogenous expression of a Eucalyptus grandis UDP-glucose dehydrogenase cDNA