AUTHOR=Kang Yajing , Wang Yingying , Hou Bingbing , Wang Ruida , Ye Jiang , Zhu Xiaoyu , Wu Haizhen , Zhang Huizhan 

TITLE=AdpAlin, a Pleiotropic Transcriptional Regulator, Is Involved in the Cascade Regulation of Lincomycin Biosynthesis in Streptomyces lincolnensis

JOURNAL=Frontiers in Microbiology

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2019.02428

DOI=10.3389/fmicb.2019.02428

ISSN=1664-302X

ABSTRACT=<p>Lincomycin is one of the most important antibiotics in clinical practice. To further understand the regulatory mechanism on lincomycin biosynthesis, we investigated a pleiotropic transcriptional regulator AdpA<sub>lin</sub> in the lincomycin producer <italic>Streptomyces lincolnensis</italic> NRRL 2936. Deletion of <italic>adpA</italic><sub><italic>lin</italic></sub> (which generated Δ<italic>adpA</italic><sub><italic>lin</italic></sub>) interrupted lincomycin biosynthesis and impaired the morphological differentiation. We also found that putative AdpA binding sites were unusually scattered in the promoters of all the 8 putative operons in the lincomycin biosynthetic gene cluster (BGC). In Δ<italic>adpA</italic><sub><italic>lin</italic></sub>, transcript levels of structural genes in 8 putative operons were decreased with varying degrees, and electrophoretic mobility shift assays (EMSAs) confirmed that AdpA<sub>lin</sub> activated the overall putative operons via directly binding to their promoter regions. Thus, we speculated that the entire lincomycin biosynthesis is under the control of AdpA<sub>lin</sub>. Besides, AdpA<sub>lin</sub> participated in lincomycin biosynthesis by binding to the promoter of <italic>lmbU</italic> which encoded a cluster sited regulator (CSR) LmbU of lincomycin biosynthesis. Results of qRT-PCR and catechol dioxygenase activity assay showed that AdpA<sub>lin</sub> activated the transcription of <italic>lmbU</italic>. In addition, AdpA<sub>lin</sub> activated the transcription of the <italic>bldA</italic> by binding to its promoter, suggesting that AdpA<sub>lin</sub> indirectly participated in lincomycin biosynthesis and morphological differentiation. Uncommon but understandable, AdpA<sub>lin</sub> auto-activated its own transcription via binding to its own promoter region. In conclusion, we provided a molecular mechanism around the effect of AdpA<sub>lin</sub> on lincomycin biosynthesis in <italic>S. lincolnensis</italic>, and revealed a cascade regulation of lincomycin biosynthesis by AdpA<sub>lin</sub>, LmbU, and BldA.</p>