An alternative σ factor σ regulates lincomycin production in Streptomyces lincolnensis.

Lincomycin produced by Streptomyces lincolnensis is a critical antibacterial antibiotic in the clinical. To further understand the regulatory mechanism of lincomycin biosynthesis, we identified an alternative σ factor, σ , in Streptomyces lincolnensis NRRL 2936. Deletion of sigL resulted in an increase in cell growth but a decrease in lincomycin production. σ boosted lincomycin biosynthesis by directly stimulating the transcription of four genes (lmbD, lmbV, lmrC, and lmbU) within the lincomycin biosynthetic lmb gene cluster. Besides, σ participated in lincomycin biosynthesis by directly stimulating the transcription of mshC, a gene responsible for MSH synthesis. In conclusion, our findings demonstrated that σ plays a direct regulatory role in lincomycin biosynthesis. This study extends the understanding of molecular mechanisms of lincomycin biosynthetic regulation.