MarR family regulator LcbR2 activates lincomycin biosynthesis in multiple ways

Area of Science:

• Microbiology
• Molecular Biology
• Biochemistry

Background:

• Lincomycin is a crucial antibiotic produced by Streptomyces lincolnensis.
• Understanding the regulation of lincomycin biosynthesis is vital for improving its production.
• Transcriptional regulators play key roles in secondary metabolite production in bacteria.

Purpose of the Study:

• To identify and characterize novel regulators involved in lincomycin biosynthesis.
• To elucidate the regulatory mechanism of LcbR2 on lincomycin production.
• To explore the broader regulatory scope of LcbR2 in Streptomyces lincolnensis.

Main Methods:

• Gene knockout experiments to assess the role of lcbR2.
• Quantitative real-time PCR (qRT-PCR) to analyze gene expression.
• Electrophoretic mobility shift assays (EMSAs) to determine DNA-binding activity.
• XylE reporter assays to quantify transcriptional activation.

Main Results:

• Deletion of lcbR2 reduced lincomycin production by 63% without affecting bacterial growth.
• LcbR2 directly binds to a specific DNA sequence and represses its own expression.
• LcbR2 directly activates lincomycin biosynthesis genes (lmbD, lmbJ, lmbK, lmbV, lmbW) and resistance genes (lmrA, lmrB).
• LcbR2 influences other regulatory genes and metabolic pathways, indicating a wide regulatory network.
• Apramycin was found to attenuate LcbR2's DNA binding.

Conclusions:

• LcbR2 is a novel and essential transcriptional activator for lincomycin biosynthesis.
• LcbR2 exhibits a broad regulatory scope, impacting biosynthesis, resistance, and metabolism.
• Targeting LcbR2 presents a promising strategy for enhancing lincomycin production.