TY - JOUR T1 - Silencing cryptic specialized metabolism in <em>Streptomyces</em> by the nucleoid-associated protein Lsr2 JF - bioRxiv DO - 10.1101/614727 SP - 614727 AU - Emma J. Gehrke AU - Xiafei Zhang AU - Sheila M. Pimentel-Elardo AU - Andrew R. Johnson AU - Christiaan A. Rees AU - Stephanie E. Jones AU - Hindra AU - Sebastian S. Gehrke AU - Sonya Turvey AU - Suzanne Boursalie AU - Jane E. Hill AU - Erin E. Carlson AU - Justin R. Nodwell AU - Marie A. Elliot Y1 - 2019/01/01 UR - http://biorxiv.org/content/early/2019/04/22/614727.abstract N2 - Lsr2 is a nucleoid-associated protein conserved throughout the actinobacteria, including the antibiotic-producing Streptomyces. Streptomyces species encode paralogous Lsr2 proteins (Lsr2 and Lsr2-like, or LsrL), and we show here that of the two, Lsr2 has greater functional significance. We found that Lsr2 binds AT-rich sequences throughout the chromosome, and broadly represses gene expression. Strikingly, specialized metabolic clusters were over-represented amongst its targets, and the cryptic nature of many of these clusters appears to stem from Lsr2-mediated repression. Manipulating Lsr2 activity in model species and uncharacterized isolates resulted in the production of new metabolites not seen in wild type strains. Our results suggest that the transcriptional silencing of biosynthetic clusters by Lsr2 may protect Streptomyces from the inappropriate expression of specialized metabolites, and provide global control over Streptomyces’ arsenal of signalling and antagonistic compounds. ER -