Characterization and Manipulation of the Pathway-Specific Late Regulator AlpW Reveals Streptomyces ambofaciens as a New Producer of Kinamycins
Characterization and Manipulation of the Pathway-Specific Late Regulator AlpW Reveals Streptomyces ambofaciens as a New Producer of Kinamycins
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DOI：
10.1128/jb.01269-10
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发表时间：
2011-03-01
影响因子：
3.2
通讯作者：
Aigle, Bertrand
中科院分区：
文献类型：
--
作者：
Bunet, Robert;Song, Lijiang;Aigle, Bertrand
已知产康戈西定和螺旋霉素抗生素的产氨链霉菌的基因组序列揭示了预测参与次级代谢物生物合成的许多基因簇的存在。其中，II型聚酮酶编码的ALP簇被证明是负责生物合成的化合物具有抗菌活性。在这里，通过放松管制的方法，我们获得了可行量的抗生素用于结构解析。这些化合物，以前被命名为alpomycin，已被证明是已知的抗生素家族的成员。事实上，一个缺乏AlpW的突变体，TetR调节家族的成员，被证明是组成性产生kinamycins。比较转录分析表明，表达的alpV，激活的生物合成基因所需的基本调节基因，强烈维持在静止生长期的alpW突变体，一个阶段，在该阶段alpV的成绩单，从而转录的生物合成基因通常下降。重组AlpW对自身基因启动子区及alpV和alpZ启动子区的特定基序显示DNA结合活性。这些识别序列也是AlpZ的靶标，AlpZ是参与alp簇调节的γ-丁内酯样受体。然而，与AlpZ不同，AlpW DNA结合能力似乎对控制抗生素生物合成的信号分子不敏感。总之，这项研究中提出的结果揭示了S。Ambofaciens是一个新的生产者的卡那霉素和AlpW是一个关键的晚期阻遏细胞控制的卡那霉素生物合成。
The genome sequence of Streptomyces ambofaciens, a species known to produce the congocidine and spiramycin antibiotics, has revealed the presence of numerous gene clusters predicted to be involved in the biosynthesis of secondary metabolites. Among them, the type II polyketide synthase-encoding alp cluster was shown to be responsible for the biosynthesis of a compound with antibacterial activity. Here, by means of a deregulation approach, we gained access to workable amounts of the antibiotics for structure elucidation. These compounds, previously designated as alpomycin, were shown to be known members of kinamycin family of antibiotics. Indeed, a mutant lacking AlpW, a member of the TetR regulator family, was shown to constitutively produce kinamycins. Comparative transcriptional analyses showed that expression of alpV, the essential regulator gene required for activation of the biosynthetic genes, is strongly maintained during the stationary growth phase in the alpW mutant, a stage at which alpV transcripts and thereby transcripts of the biosynthetic genes normally drop off. Recombinant AlpW displayed DNA binding activity toward specific motifs in the promoter region of its own gene and that of alpV and alpZ. These recognition sequences are also targets for AlpZ, the gamma-butyrolactone-like receptor involved in the regulation of the alp cluster. However, unlike that of AlpZ, the AlpW DNA-binding ability seemed to be insensitive to the signaling molecules controlling antibiotic biosynthesis. Together, the results presented in this study reveal S. ambofaciens to be a new producer of kinamycins and AlpW to be a key late repressor of the cellular control of kinamycin biosynthesis.