SapB and the chaplins: connections between morphogenetic proteins in Streptomyces coelicolor
| Autor: | Mark J. Buttner, Joanne M. Willey, Marie A. Elliot, David S. Capstick |
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| Rok vydání: | 2007 |
| Předmět: |
Hypha
Immunoblotting Mutant Morphogenesis Streptomyces coelicolor Microbiology chemistry.chemical_compound Bacterial Proteins Biosynthesis Mannitol Secretion Molecular Biology biology Streptomycetaceae fungi food and beverages Gene Expression Regulation Bacterial biology.organism_classification Culture Media DNA-Binding Proteins Phenotype chemistry Biochemistry Spectrometry Mass Matrix-Assisted Laser Desorption-Ionization Mutation Actinomycetales Gene Deletion Plasmids Signal Transduction Transcription Factors |
| Zdroj: | Molecular Microbiology. 64:602-613 |
| ISSN: | 1365-2958 0950-382X |
| Popis: | Summary Morphogenesis in the streptomycetes features the differentiation of substrate-associated vegetative hyphae into upwardly growing aerial filaments. This transition requires the activity of bld genes and the secretion of biosurfactants that reduce the surface tension at the colony-air interface enabling the emergence of nascent aerial hyphae. Streptomyces coelicolor produces two classes of surface-active molecules, SapB and the chaplins. While both mol- ecules are important for aerial development, nothing is known about the functional redundancy or interac- tion of these surfactants apart from the observation that aerial hyphae formation can proceed via one of two pathways: a SapB-dependent pathway when cells are grown on rich medium and a SapB-independent pathway on poorly utilized carbon sources such as mannitol. We used mutant analysis to show that while the chaplins are important, but not required, for devel- opment on rich medium, they are essential for differ- entiation on MS (soy flour mannitol) medium, and the corresponding developmental defects could be sup- pressed by the presence of SapB. Furthermore, the chaplins are produced by conditional bld mutants during aerial hyphae formation when grown on the permissive medium, MS, suggesting that the previ- ously uncharacterized SapB-independent pathway is chaplin dependent. In contrast, a bld mutant blocked in aerial morphogenesis on all media makes neither SapB nor chaplins. Finally, we show that a con- structed null mutant that lacks all chaplin and SapB biosynthetic genes fails to differentiate in any growth condition. We propose that the biosurfactant activi- ties of both SapB and the chaplins are essential for normal aerial hyphae formation on rich medium, while chaplin biosynthesis and secretion alone drives aerial morphogenesis on MS medium. |
| Databáze: | OpenAIRE |
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