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The RNA polymerase‐binding protein RbpA confers basal levels of rifampicin resistance on Streptomyces coelicolor
Author(s) -
Newell Katy V.,
Thomas Derek P.,
Brekasis Dimitris,
Paget Mark S. B.
Publication year - 2006
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2006.05116.x
Subject(s) - streptomyces coelicolor , biology , sigma factor , rna polymerase , operon , transcription (linguistics) , mutant , microbiology and biotechnology , rifampicin , ribosomal protein , rna , ribosomal rna , rna polymerase i , genetics , gene , ribosome , antibiotics , linguistics , philosophy
Summary RbpA is an RNA polymerase‐binding protein that occurs in the actinomycete family of bacteria and is regulated by the disulphide stress‐response sigma factor, σ R , in Streptomyces coelicolor . Here we demonstrate that rbpA null mutants exhibit a slow‐growth phenotype and are particularly sensitive to the transcription inhibitor rifampicin. Strikingly, transcription mapping experiments revealed that rbpA expression is induced upon exposure of S. coelicolor to rifampicin and that this, in part, involves an increase in the activity of σ R . In contrast, the ribosomal RNA operon promoter rrnDp3 , which is recognized by the vegetative sigma factor σ HrdB , was strongly inhibited by rifampicin. Reconstitution of RNAP from an rbpA null mutant with purified RbpA revealed that RbpA stimulates transcription from rrnDp3 , even in the presence of rifampicin. The data presented suggest that RbpA confers basal levels of rifampicin resistance and is a novel regulator of rRNA synthesis in S. coelicolor .