Dataset Information

Developmental delay in a Streptomyces venezuelae glgE null mutant is associated with the accumulation of ?-maltose 1-phosphate.

ABSTRACT: The GlgE pathway is thought to be responsible for the conversion of trehalose into a glycogen-like ?-glucan polymer in bacteria. Trehalose is first converted to maltose, which is phosphorylated by maltose kinase Pep2 to give ?-maltose 1-phosphate. This is the donor substrate of the maltosyl transferase GlgE that is known to extend ?-1,4-linked maltooligosaccharides, which are thought to be branched with ?-1,6 linkages. The genome of Streptomyces venezuelae contains all the genes coding for the GlgE pathway enzymes but none of those of related pathways, including glgC and glgA of the glycogen pathway. This provides an opportunity to study the GlgE pathway in isolation. The genes of the GlgE pathway were upregulated at the onset of sporulation, consistent with the known timing of ?-glucan deposition. A constructed ?glgE null mutant strain was viable but showed a delayed developmental phenotype when grown on maltose, giving less cell mass and delayed sporulation. Pre-spore cells and spores of the mutant were frequently double the length of those of the wild-type, implying impaired cross-wall formation, and spores showed reduced tolerance to stress. The mutant accumulated ?-maltose 1-phosphate and maltose but no ?-glucan. Therefore, the GlgE pathway is necessary and sufficient for polymer biosynthesis. Growth of the ?glgE mutant on galactose and that of a ?pep2 mutant on maltose were analysed. In both cases, neither accumulation of ?-maltose 1-phosphate/?-glucan nor a developmental delay was observed. Thus, high levels of ?-maltose 1-phosphate are responsible for the developmental phenotype of the ?glgE mutant, rather than the lack of ?-glucan.

SUBMITTER: Miah F

PROVIDER: S-EPMC5042117 | biostudies-literature | 2016 Jul

REPOSITORIES: biostudies-literature

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Developmental delay in a Streptomyces venezuelae glgE null mutant is associated with the accumulation of α-maltose 1-phosphate.

Miah Farzana F Bibb Maureen J MJ Barclay J Elaine JE Findlay Kim C KC Bornemann Stephen S

Microbiology (Reading, England) 20160426 7

The GlgE pathway is thought to be responsible for the conversion of trehalose into a glycogen-like α-glucan polymer in bacteria. Trehalose is first converted to maltose, which is phosphorylated by maltose kinase Pep2 to give α-maltose 1-phosphate. This is the donor substrate of the maltosyl transferase GlgE that is known to extend α-1,4-linked maltooligosaccharides, which are thought to be branched with α-1,6 linkages. The genome of Streptomyces venezuelae contains all the genes coding for the G ...[more]

PMID: 27121970

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Project description:In members of genus Streptomyces, AdpA is a master transcriptional regulator that controls the expression of hundreds of genes involved in morphological differentiation, secondary metabolite biosynthesis, chromosome replication, etc. However, the function of AdpASv, an AdpA ortholog of Streptomyces venezuelae, is unknown. This bacterial species is a natural producer of chloramphenicol and has recently become a model organism for studies on Streptomyces. Here, we demonstrate that AdpASv is essential for differentiation and antibiotic biosynthesis in S. venezuelae and provide evidence suggesting that AdpASv positively regulates its own gene expression. We speculate that the different modes of AdpA-dependent transcriptional autoregulation observed in S. venezuelae and other Streptomyces species reflect the arrangement of AdpA binding sites in relation to the transcription start site. Lastly, we present preliminary data suggesting that AdpA may undergo a proteolytic processing and we speculate that this may potentially constitute a novel regulatory mechanism controlling cellular abundance of AdpA in Streptomyces. IMPORTANCEStreptomyces are well-known producers of valuable secondary metabolites which include a large variety of antibiotics and important model organisms for developmental studies in multicellular bacteria. The conserved transcriptional regulator AdpA of Streptomyces exerts a pleiotropic effect on cellular processes, including the morphological differentiation and biosynthesis of secondary metabolites. Despite extensive studies, the function of AdpA in these processes remains elusive. This work provides insights into the role of a yet unstudied AdpA ortholog of Streptomyces venezuelae, now considered a novel model organism. We found that AdpA plays essential role in morphological differentiation and biosynthesis of chloramphenicol, a broad-spectrum antibiotic. We also propose that AdpA may undergo a proteolytic processing that presumably constitutes a novel mechanism regulating cellular abundance of this master regulator.

Dataset Information

Developmental delay in a Streptomyces venezuelae glgE null mutant is associated with the accumulation of ?-maltose 1-phosphate.

Publications

Developmental delay in a Streptomyces venezuelae glgE null mutant is associated with the accumulation of α-maltose 1-phosphate.

Similar Datasets

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