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Regulation of tylosin biosynthesis involving ‘SARP‐helper’ activity
Author(s) -
Bate Neil,
Bignell Dawn R. D.,
Cundliffe Eric
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.1365-2958.2006.05338.x
Subject(s) - tylosin , streptomyces fradiae , biology , repressor , activator (genetics) , polyketide , biosynthesis , gene , secondary metabolism , streptomyces , actinomycetales , streptomycetaceae , biochemistry , genetics , gene expression , bacteria , antibiotics
Summary Tylosin production in Streptomyces fradiae is regulated via interplay between a repressor, TylQ, and an activator of the SARP family, TylS, during regulation of tylR . The latter encodes the pathway‐specific activator of the tylosin‐biosynthetic ( tyl ) genes. Also controlled by TylS is a hitherto unassigned gene, tylU , whose product is shown here to be important for tylosin production. Thus, targeted disruption of tylU reduced tylosin yields by about 80% and bioconversion analysis with the resultant strain revealed defects in both polyketide metabolism and deoxyhexose biosynthesis. Such defects were completely eliminated by engineered overexpression of tylR (but not tylS ) and Western analysis revealed significantly reduced levels of TylR in the tylU ‐disrupted strain. These results are consistent with a model in which TylS and TylU act in concert to facilitate expression of tylR , for which TylU (but not TylS) is nonessential. Activator proteins of the SARP family, such as TylS, are widespread among Streptomyces spp. and are important regulators of antibiotic production. Their action has been widely studied with no prior indication of associated ‘helper’ activity, the prevalence of which now remains to be established.