Constructing a bacterial skyscraper: from gene regulation to cell wall proteins

Streptomycetes are abundant Gram positive bacteria that are characterized by a complex life cycle. They colonize dead and living organic material by means of hyphae that grow at their apices. The hyphae are part of an interconnected network, which is called a mycelium. At a certain moment, hyphae grow out of the substrate into the air. The resulting aerial hyphae septate to form chains of spores that, after dispersal, give rise to new mycelia. Deletion studies performed in our group have indicated the existence of a novel regulatory pathway in Streptomyces coelicolor, the skyscraper pathway, that is involved in aerial growth as well as in hyphal attachment to hydrophobic surfaces. The research described in this proposal aims at unraveling the skyscraper pathway and at the identification and characterization of target genes, among which those encoding cell wall proteins. This research will contribute to our understanding of developmental processes involved in microbial aerial growth. Moreover, it may provide mechanisms by which pathogenic streptomycetes and related actinomycetes attach to surfaces of their host, thus enabling the initiation of infection.