Conditional Effect of the Deletion of eshA on Streptomycin Production in Streptomyces griseus IFO13350

Abstract

The eshA gene was originally found to encode a protein required for the extension of sporogenic hyphae during submerged spore formation in Streptomyces griseus NRRL B-2682. An eshA-disrupted strain of S. griseus IFO13189 was reported to be conditionally deficient in streptomycin production and aerial mycelium formation. Our previous transcriptomic analyses indicated that AdpA, a global transcriptional regulator of morphological and physiological differentiation, induced eshA (SGR1270) transcription in S. griseus IFO13350. Here, we examined the transcriptional regulation of eshA by AdpA and the involvement of eshA in the morphological and physiological differentiation of S. griseus IFO13350. Transcriptional analysis by S1 nuclease mapping showed that eshA was transcribed throughout growth on solid medium. In contrast, no eshA transcription was detected in an adpA deletion mutant. Recombinant His-tagged AdpA bound to a region upstream from the eshA promoter in vitro. However, mutation of the AdpA-binding sequence did not affect the transcription of eshA in vivo, indicating that AdpA indirectly activates eshA transcription. Streptomycin production by an eshA deletion mutant grown on TSB plates was lower than that of the wild-type strain. However, the eshA deletion mutant grew and formed aerial mycelia and spores following the same time course as the wild-type strain on various media.