Multiple extracellular signals govern the production of a morphogenetic protein involved in aerial mycelium formation by Streptomyces coelicolor.
The formation of an aerial mycelium by the filamentous bacterium Streptomyces coelicolor is determined in part by a small morphogenetic protein called SapB. A collection of representative bald (bld) mutants, which are blocked in aerial mycelium formation, are all defective in the production of this protein and regain the capacity to undergo morphological differentiation when SapB is supplied exogenously. We now report that most of the bld mutants are rescued for SapB production and aerial mycelium formation when grown near certain other bld mutants. Extracellular complementation experiments of this kind indicate that morphological differentiation is governed by a hierarchical cascade of at least four kinds of intercellular signals. At least one such signal is present in conditioned medium. It is resistant to boiling and protease treatment, and it remains effective even when diluted up to eightfold in fresh medium.
Biological Laboratories, Harvard University, Cambridge, Massachusetts 02138.
J
J
Willey
J
J
Schwedock
R
R
Losick
D000328:Adult; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics*; D015153:Blotting, Western; D002701:Chloramphenicol / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D019286:Endopeptidase K; D005798:Genes, Bacterial / Q000502:physiology; D006358:Hot Temperature; D006801:Humans; D009024:Morphogenesis / Q000235:genetics; D009154:Mutation; D012697:Serine Endopeptidases / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D013302:Streptomyces / Q000187:drug effects / Q000235:genetics / Q000254:growth & development*
D001426:Bacterial Proteins; C055447:Streptomyces spore-associated proteins; D002701:Chloramphenicol; D012697:Serine Endopeptidases; D019286:Endopeptidase K