Regulatory networks play critical roles in controlling the the biosynthesis of natural products in Streptomyces. ActVI-ORFA, a regulatory factor encoded by the actinorhodin biosynthetic gene cluster (act cluster), positively controls the production of actinorhodin (ACT) in Streptomyces coelicolor, although its regulatory mechanism remains obscure. This study aimed to identify the regulatory targets of ActVI-ORFA. Deletion of ActVI-ORFA caused the differential expression of hundreds of proteins, as determined by two-dimensional electrophoresis and peptide mass fingerprinting analysis. qRT-PCR analysis of some genes encoding these differentially expressed proteins, including act genes and non-act genes, confirmed that ActVI-ORFA could control their transcriptional levels. In an electrophoretic mobility shift assay with a promoter region of a target gene located in the act cluster, no binding was detected, consistent with the lack of a recognizable DNA-binding domain in ActVI-ORFA. Overall, our findings suggest that ActVI-ORFA is a pleiotropic regulatory factor that controls multiple physiological pathways, including secondary metabolite production, probably via an indirect mode.

调节网络在控制链霉菌中天然产物的生物合成方面发挥着关键作用。ActVI-ORFA 是一种由放线菌素生物合成基因簇 ( act簇)编码的调节因子，可正向控制天蓝色链霉菌中放线菌素 (ACT) 的产生，但其调节机制仍不清楚。本研究旨在确定 ActVI-ORFA 的监管目标。二维电泳和肽质量指纹分析确定，ActVI-ORFA 的缺失导致数百种蛋白质的差异表达。对编码这些差异表达蛋白的一些基因进行 qRT-PCR 分析，包括行为基因和非行为基因基因，证实了 ActVI-ORFA 可以控制它们的转录水平。在使用位于act簇中的靶基因的启动子区域进行的电泳迁移率变化测定中，未检测到结合，这与 ActVI-ORFA 中缺乏可识别的 DNA 结合域一致。总体而言，我们的研究结果表明，ActVI-ORFA 是一种多效调节因子，可能通过间接模式控制多种生理途径，包括次级代谢产物的产生。