We have constructed derivatives of Streptomyces coelicolor M145 as hosts for the heterologous expression of secondary metabolite gene clusters. To remove potentially competitive sinks of carbon and nitrogen, and to provide a host devoid of antibiotic activity, we deleted four endogenous secondary metabolite gene clusters from S. coelicolor M145 – those for actinorhodin, prodiginine, CPK and CDA biosynthesis. We then introduced point mutations into rpoB and rpsL to pleiotropically increase the level of secondary metabolite production. Introduction of the native actinorhodin gene cluster and of gene clusters for the heterologous production of chloramphenicol and congocidine revealed dramatic increases in antibiotic production compared with the parental strain. In addition to lacking antibacterial activity, the engineered strains possess relatively simple extracellular metabolite profiles. When combined with liquid chromatography and mass spectrometry, we believe that these genetically engineered strains will markedly facilitate the discovery of new compounds by heterologous expression of cloned gene clusters, particularly the numerous cryptic secondary metabolic gene clusters that are prevalent within actinomycete genome sequences.

中文翻译：

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工程化天蓝色链霉菌用于次生代谢物基因簇的异源表达。

我们已经构建了天蓝色链霉菌M145 的衍生物作为次级代谢物基因簇异源表达的宿主。为了去除潜在的竞争性碳和氮汇，并提供没有抗生素活性的宿主，我们从S. coelicolor M145 中删除了四个内源性次生代谢物基因簇——用于放线菌素、prodiginine、CPK 和 CDA 生物合成的基因簇。然后我们将点突变引入rpoB和rpsL多效性提高次生代谢产物的水平。引入天然放线菌素基因簇和用于异源生产氯霉素和刚果核苷的基因簇显示，与亲本菌株相比，抗生素产量显着增加。除了缺乏抗菌活性外，工程菌株还具有相对简单的细胞外代谢物谱。当与液相色谱和质谱相结合时，我们相信这些基因工程菌株将显着促进通过克隆基因簇的异源表达发现新化合物，特别是放线菌基因组序列中普遍存在的众多神秘的次级代谢基因簇。