Insight into the Molecular Mechanism of the Transcriptional Regulation of amtB Operon in Streptomyces coelicolor.
Insight into the Molecular Mechanism of the Transcriptional Regulation of amtB Operon in Streptomyces coelicolor.
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天蓝色链霉菌amtB操纵子转录调控的分子机制研究
DOI：
10.3389/fmicb.2018.00264
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发表时间：
2018
影响因子：
5.2
通讯作者：
Wang J
中科院分区：
文献类型：
--
作者：
Li Z;Liu X;Wang J;Wang Y;Zheng G;Lu Y;Zhao G;Wang J
在天蓝色链霉菌中，amtB转录迅速受到全球氮调节因子GlnR的调控。虽然已经在amtB启动子中鉴定了GlnR结合顺式元件，由a3-b3、a1-b1和a2-b2三个GlnR框组成，但它在GlnR介导的转录调控中的作用尚不清楚。在这里，我们发现GlnR与amtB启动子上的每一对GlnR结合位点(即a3-b3、a1-b1和a2-b2位点)具有不同的结合亲和力，并且GlnR分别能够结合a3-b3和a1-b1，但不能单独结合a2-b2。A2始终不是典型的GlnR结合部位，进一步的实验表明a2对GlnR介导的体外结合和体内转录调控都不是必需的。为了揭示三个GlnR盒的生理作用，我们将野生型amtB启动子突变为含有两个GlnR盒(a3-b3-a2-b2)的典型GlnR结合基序，发现虽然突变的启动子仍能被GlnR激活，但其增长速度低于野生型。根据这些发现，人们可以得出结论，这三个GlnR盒帮助GlnR更迅速地激活amtB转录，以响应氮限制，促进细菌在氮胁迫下的生长。
In Streptomyces coelicolor, amtB transcription is promptly regulated by the global nitrogen regulator GlnR. Although the GlnR binding cis-element has been characterized in amtB promoter, consisting of three GlnR boxes of a3-b3, a1-b1, and a2-b2, its role in GlnR-mediated transcriptional regulation remains unclear. Here, we showed that GlnR had different binding affinity against each pair of GlnR binding sites in amtB promoter (i.e., a3-b3, a1-b1, and a2-b2 sites), and GlnR was able to bind a3-b3 and a1-b1, respectively, but not a2-b2 alone. Consistently, a2 was not a typical GlnR binding site and further experiments showed that a2 was non-essential for GlnR-mediated binding in vitro and transcriptional regulation in vivo. To uncover the physiological role of the three GlnR boxes, we then mutated the wild-type amtB promoter to a typical GlnR-binding motif containing two GlnR boxes (a3-b3–a2-b2), and found although the transcription of the mutated promoter could still be activated by GlnR, its increasing rate was less than that of the wild-type. Based on these findings, one could conclude that the three GlnR boxes assisted GlnR in more promptly activating amtB transcription in response to nitrogen limitation, facilitating bacterial growth under nitrogen stresses.
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影响因子：
3.6
作者：
Sola-Landa, A;Rodríguez-García, A;Martín, JF
通讯作者：
Martín, JF
影响因子：
2.8
作者：
Apel, Alexander K.;Sola-Landa, Alberto;Martin, Juan F.
通讯作者：
Martin, Juan F.
影响因子：
1.8
作者：
Lewis RA;Shahi SK;Laing E;Bucca G;Efthimiou G;Bushell M;Smith CP
通讯作者：
Smith CP
DOI：
10.1073/pnas.0337542100
发表时间：
2003-02-18
影响因子：
11.1
作者：
Gust, B;Challis, GL;Chater, KF
通讯作者：
Chater, KF
影响因子：
14.9
作者：
Sola-Landa A;Rodríguez-García A;Amin R;Wohlleben W;Martín JF
通讯作者：
Martín JF