Characterization of rrdA, a TetR Family Protein Gene Involved in the Regulation of Secondary Metabolism in Streptomyces coelicolor
Characterization of rrdA, a TetR Family Protein Gene Involved in the Regulation of Secondary Metabolism in Streptomyces coelicolor
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rrdA（参与天蓝色链霉菌次生代谢调节的 TetR 家族蛋白基因）的表征
DOI：
10.1128/aem.02209-08
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发表时间：
2009-04-01
影响因子：
4.4
通讯作者：
Ding, Xiaoming
中科院分区：
文献类型：
--
作者：
Ou, Xijun;Zhang, Bo;Ding, Xiaoming
摘要链霉菌不仅具有复杂的形态分化，而且产生过多的次生代谢物，尤其是抗生素。为了加深对十一烷基灵芝红素(Red)生物合成调控的复杂网络的了解，我们使用体内转座系统来鉴定影响天蓝色链霉菌M145中Red合成的新调节子。利用该筛选体系，我们获得了25个红色缺失突变体。其中24个突变株在前面描述的Red生物合成基因簇中插入了转座子，并产生了不同数量的另一种次生代谢物放线菌素(Act)。一个突变体被证明在之前未鉴定的基因rrdA(RedD的调节基因，cod1104)的上游染色体的不同区域有一个插入，该基因编码一个可能的TetR家族转录因子。与野生型菌株M145相比，rrdA缺失突变体的红色产量增加，Act产量降低。高水平的rrdA表达导致红色产量和ACT产量过剩的严重减少。逆转录-聚合酶链式反应分析表明，RrdA通过控制Redd基因的丰度来负调控Red的产生，而Act特异性激活基因actII-orf4的转录水平没有观察到变化。对ACT生物合成的影响可能来自对两条途径共同的前体的竞争。
ABSTRACT Streptomyces not only exhibits complex morphological differentiation but also produces a plethora of secondary metabolites, particularly antibiotics. To improve our general understanding of the complex network of undecylprodigiosin (Red) biosynthesis regulation, we used an in vivo transposition system to identify novel regulators that influence Red production in Streptomyces coelicolor M145. Using this screening system, we obtained 25 Red-deficient mutants. Twenty-four of these mutants had a transposon inserted in the previously described Red biosynthetic gene cluster and produced different amounts of another secondary metabolite, actinorhodin (Act). One mutant was shown to have an insertion in a different region of the chromosome upstream of the previously uncharacterized gene rrdA (regulator of redD, sco1104), which encodes a putative TetR family transcription factor. Compared with wild-type strain M145, the rrdA null mutant exhibited increased Red production and decreased Act production. A high level of rrdA expression resulted in a severe reduction in Red production and Act overproduction. Reverse transcription-PCR analysis showed that RrdA negatively regulated Red production by controlling redD mRNA abundance, while no change was observed at the transcript level of the Act-specific activator gene, actII-orf4. The effects on Act biosynthesis might arise from competition for precursors that are common to both pathways.