The ECF sigma factor SigT regulates actinorhodin production in response to nitrogen stress in Streptomyces coelicolor
The ECF sigma factor SigT regulates actinorhodin production in response to nitrogen stress in Streptomyces coelicolor
复制标题
ECF sigma 因子 SigT 调节天蓝色链霉菌响应氮胁迫的放线菌素产生
DOI：
10.1007/s00253-011-3619-2
复制
发表时间：
2011-12-01
影响因子：
5
通讯作者：
Li, Yong-Quan
中科院分区：
文献类型：
--
作者：
Feng, Wei-Hong;Mao, Xu-Ming;Li, Yong-Quan
胞浆外功能（ECF）亚家族的Sigma因子是细菌应激反应的重要调节因子。本文描述了彩色链霉菌ECF sigma因子SigT的特征。我们发现，在氮胁迫下，sigT的缺失几乎消除了抗生素放线菌素（Act）的产生。在氮限制条件下，与野生型相比，在sight -null突变体中观察到显著减少的Act产量和关联的actII-ORF4转录。利用报告基因（xylE）与sigT启动子的融合，我们证明了氮限制诱导sigT以依赖于sigT的方式发生。转录分析表明，SigT控制ppGpp合成酶基因relA的表达，从而影响氮饥饿时Act的产生。共转录分析显示，sigT与sigT上游基因rstB共转录，而与sigT下游基因rstA共转录。表型和转录结果表明RstA可能正向调节SigT的活性。
Sigma factors of the extracytoplasmic function (ECF) subfamily are important regulators of stress responses in bacteria. This work described the characterization of ECF sigma factor SigT in Streptomyces coelicolor. We found the absence of sigT almost abolished the production of the antibiotics actinorhodin (Act) under nitrogen stress. Under nitrogen-limited conditions, significantly reduced Act production and linked actII-ORF4 transcription with respect to wild type were observed in the sigT-null mutant. Using reporter (xylE) fusion to sigT promoter, we demonstrated that sigT was induced by nitrogen limitation in a SigT-dependent manner. Transcriptional analyses showed that SigT controlled the expression of relA, the ppGpp synthetase gene, and consequently affected the Act production upon nitrogen starvation. Co-transcription analysis revealed that sigT was co-transcribed with rstB (gene upstream of sigT) but not with rstA (gene downstream of sigT). Phenotypic and transcriptional results suggested RstA may modulate the activity of SigT positively.