A new TetR family transcriptional regulator required for morphogenesis in Streptomyces coelicolor
A new TetR family transcriptional regulator required for morphogenesis in Streptomyces coelicolor
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DOI：
10.1128/jb.01316-07
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发表时间：
2008-01-01
影响因子：
3.2
通讯作者：
Westpheling, Janet
中科院分区：
文献类型：
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作者：
Hillerich, Brandan;Westpheling, Janet
链霉菌的形态发生和抗生素的产生都是对饥饿的反应，并且这些事件是耦合的。我们先前描述了天蓝色链霉菌SE 293中的转座子产生的突变体，其导致过量产生抗生素放线菌紫素的bld菌株。通过插入鉴定的SCO 1135开放阅读框编码转录调节因子TetR家族的成员。在这里，我们表明，一个构建的SCO 1135开放阅读框架删除导致相同的形态和抗生素生产表型的插入突变体。构建的缺失也导致SCO 1135转录本的组成型表达，以及与之紧邻的基因簇SCO 1134 -1132的组成型表达，SCO 1134 -1132编码推定的多巴胺结合复合物。SCO 1135蛋白产物的His（6）标记版本显示结合SCO 1135和SCO 1134之间的基因间区域，该区域包含通过引物延伸分析定位的每个基因的表观转录起始位点。SCO 1135缺失突变体中SCO 1134 -1132转录物的表达增加也导致黄嘌呤脱氢酶活性的表达增加，证实了基于蛋白质相似性构建的关于这些开放阅读的预测。我们将SCO 1134 -1142基因簇命名为xdhABC，并将SCO 1135编码的调节子命名为xdhR。我们推测，黄嘌呤脱氢酶的不适当的表达影响嘌呤抢救途径在发展的开始，创造人为的高浓度的GTP和ppGpp和扰乱这些分子参与的途径的形态发生和抗生素生产的启动。
Both morphogenesis and antibiotic production in the streptomycetes are initiated in response to starvation, and these events are coupled. We previously described a transposon-generated mutant in Streptomyces coelicolor, SE293, that resulted in a bld strain that overproduced the antibiotic actinorhodin. The SCO1135 open reading frame identified by the insertion encodes a member of the TetR family of transcriptional regulators. Here we show that a constructed deletion of the SCO1135 open reading frame resulted in the same morphological and antibiotic production phenotype as the insertion mutant. The constructed deletion also resulted in constitutive expression of SCO1135 transcript, as well as that of the gene cluster immediately adjacent to it, SCO1134-1132, which encodes a putative molybdopterin binding complex. A His(6)-tagged version of the SCO1135 protein product was shown to bind the intergenic region between SCO1135 and SCO1134, which contains the apparent transcription start sites for each gene mapped by primer extension analysis. Increased expression of the SCO1134-1132 transcript in the SCO1135 deletion mutant also resulted in increased expression of xanthine dehydrogenase activity, confirming the predictions about these open reading framed based on protein similarity. We have designated the SCO1134-1142 gene cluster xdhABC and the regulator encoded by SCO1135 xdhR. We speculate that the inappropriate expression of xanthine dehydrogenase affects purine salvaging pathways at the onset of development, creating artificially high concentrations of both GTP and ppGpp and perturbing the pathways these molecules participate in for the initiation of morphogenesis and antibiotic production.