School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, China; Key Laboratory of Chinese Medicinal Resource from Lingnan, Ministry of Education and Research Center of Chinese Herbal Resource Science and Engineering, Guangzhou University of Chinese Medicine, Guangzhou 510006, China.
School of Marine Sciences, Sun Yat-Sen University, Guangzhou 510006, China.
Gene. 2025 Jan 15;933:148962. doi: 10.1016/j.gene.2024.148962. Epub 2024 Sep 24.
Actinomycins are a class of cyclic lipopeptide antibiotics produced by Streptomyces, which have rich biological activities and demonstrate great potential value. Among them, actinomycin D is currently the effective drug for some malignant tumor diseases. Although the chemical properties, biological activities and biosynthesis of actinomycins have been extensively studied, the regulation of their biosynthesis remains poorly understood. Streptomyces antibioticus ZS isolated from deep-sea corals is a producer of actinomycin D and actinomycin V. Here, we reported the characterization of a cluster-situated regulator ActO in actinomycins biosynthetic gene cluster (act cluster) of S. antibioticus ZS, which belongs to LmbU family. Deletion of actO completely blocked the synthesis of actinomycins. Overexpression of actO increased the yields of actinomycin D and actinomycin V by 4.4 fold and 2.6 fold, respectively. The result of RT-qPCR showed that ActO activates the transcription of all genes in act cluster. However, no specific binding of His-ActO to the promoters of target genes was observed after electrophoretic mobility shift assay (EMSA). These results proved that ActO serves as a positive regulator involved in the biosynthesis of actinomycins, affecting the transcription of all genes related to the synthesis of intermediates, skeleton modification and extracellular transportation of final products. Moreover, we demonstrated that overexpression of actO is a novel strategy to increase the yields of actinomycins.
放线菌素是一类由链霉菌产生的具有丰富生物活性的环脂肽类抗生素，具有巨大的潜在价值。其中，放线菌素 D 是目前治疗某些恶性肿瘤疾病的有效药物。尽管放线菌素的化学性质、生物活性和生物合成已经得到了广泛的研究，但它们的生物合成调控仍知之甚少。从深海珊瑚中分离得到的链霉菌抗生素 S. antibioticus ZS 是放线菌素 D 和 V 的产生菌。在这里，我们报道了链霉菌抗生素生物合成基因簇（act 簇）中一个位于簇内的调节剂 ActO 的特征，它属于 LmbU 家族。actO 的缺失完全阻断了放线菌素的合成。ActO 的过表达分别使放线菌素 D 和 V 的产量增加了 4.4 倍和 2.6 倍。RT-qPCR 的结果表明，ActO 激活了 act 簇中所有基因的转录。然而，在电泳迁移率变动分析（EMSA）中没有观察到 His-ActO 与靶基因启动子的特异性结合。这些结果证明，ActO 作为一个正调控因子参与放线菌素的生物合成，影响与中间体合成、骨架修饰和最终产物的细胞外运输相关的所有基因的转录。此外，我们证明了过表达 actO 是提高放线菌素产量的一种新策略。
