Open AccessTranscriptional Control by A-Factor ofstrR, the Pathway-Specific Transcriptional Activator for Streptomycin Biosynthesis inStreptomyces griseus
Author(s) -
Ayami Tomono,
Yisan Tsai,
Haruka Yamazaki,
Yasuo Ohnishi,
Sueharu Horinouchi
Publication year - 2005
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.187.16.5595-5604.2005
Subject(s) - biology , streptomyces griseus , operon , footprinting , transcription (linguistics) , transcriptional regulation , rna polymerase , gene , regulation of gene expression , transcription factor , activator (genetics) , dna footprinting , promoter , mutant , gene expression , genetics , microbiology and biotechnology , rna , streptomyces , bacteria , linguistics , philosophy
A-factor (2-isocapryloyl-3R-hydroxymethyl-gamma-butyrolactone) triggers streptomycin production by inducing the transcription of strR, encoding the pathway-specific transcriptional activator, through signal transduction in the A-factor regulatory cascade in Streptomyces griseus. AdpA, one of the key transcriptional activators in the cascade, bound two upstream activation sites, approximately at nucleotide positions -270 and -50 with respect to the transcriptional start point of strR, as determined by gel mobility shift assays and DNase I footprinting. Transcriptional analysis of the strR promoter with mutated AdpA-binding sites showed that both sites were required for full transcriptional activation of strR by AdpA. Potassium permanganate footprinting showed that AdpA assisted RNA polymerase in forming an open complex at an appropriate position for transcriptional initiation of strR. Nine transcriptional units within the streptomycin biosynthesis gene cluster, including the strR-aphD operon, depended on StrR, indicating that StrR is the pathway-specific transcriptional activator for the whole gene cluster. Consistent with this, expression of strR under the control of a constitutively expressed promoter in an adpA null mutant caused the host to produce streptomycin.