Identification and Characterization of CdgB, a Diguanylate Cyclase Involved in Developmental Processes in Streptomyces coelicolor

We describe the identification and functional characterization ofcdgB (SCO4281), a recently discovered target of BldD, a key regulator of morphological differentiation and antibiotic production in the mycelial bacteria of the genusStreptomyces .cdgB (c yclicd imericG MP [c-di-GMP]B ) encodes a GGDEF-containing protein that has diguanylate cyclase activityin vitro . Consistent with this enzymatic activity, heterologous expression ofcdgB inEscherichia coli resulted in increased production of extracellular matrix in colonies and enhanced surface attachment of cells in standing liquid cultures. InStreptomyces coelicolor , both overexpression and deletion ofcdgB inhibited aerial-mycelium formation, and overexpression also inhibited production of the antibiotic actinorhodin, implicating c-di-GMP in the regulation of developmental processes inStreptomyces .