The stress-response sigma factor σH controls the expression of ssgB, a homologue of the sporulation-specific cell division gene ssgA, in Streptomyces coelicolor A3(2)
The stress-response sigma factor σH controls the expression of ssgB, a homologue of the sporulation-specific cell division gene ssgA, in Streptomyces coelicolor A3(2)
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DOI：
10.1007/s00438-002-0687-0
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发表时间：
2002-05
影响因子：
3.1
通讯作者：
J. Kormanec;B. Ševčíková
中科院分区：
文献类型：
--
作者：
J. Kormanec;B. Ševčíková
通过使用先前建立的方法来鉴定由RNA聚合酶的特定sigma因子识别的启动子，我们鉴定了一个启动子inStreptomyces coelicolorA3(2)，该启动子被含有晚孢子特异性sigma因子σF的异源RNA聚合酶识别。该启动子引导了一个名为ssgb的基因的表达，该基因与产孢特异性细胞分裂基因ga有关。这些基因与另外三个基因一起构成了链霉菌特有的一个新的同源基因家族。在σF的控制下，利用大肠杆菌（escherichia coli）制备的RNA对s1 -核酸酶进行定位。coelicolorA3(2)在不同发育阶段发现了相同的转录起点，对应于启动子ssgbp。启动子是发育调节的inS。青色：在气生菌丝形成时产生，在产孢时最活跃。然而，在s的一个突变体中，thessgBtranscript的水平不受影响。coelicolorA3(2)。有趣的是，在该基因突变的anS. coelicolor菌株中，转录物水平大幅降低，该基因编码对孢子生成inS至关重要的应激反应σ因子（σH）。coelicolorA3(2)。通过体外转录实验证实了ssgbuponsig的依赖性，其中σH，在存在这些的情况下。cocolicolorcore RNA聚合酶能够识别gbp。这些结果表明：色系ssgBgene受应力响应σH的控制。研究了ssgb1的转录。coelicolorA3(2)突变体，在孢子分离所需的六种已知早期白色基因中每一种都有损伤。在三个突变体（whiA，whiI和whj）中，ssgb2的表达被解除调控。基于这些数据，我们提出该基因产物在inS的发育过程中起作用。coelicolorA3(2)。
By using a previously established method for the identification of promoters recognized by a particular sigma factor of RNA polymerase, we identified a promoter inStreptomyces coelicolorA3(2) that is recognized by a heterologous RNA polymerase containing the late sporulation-specific sigma factor σF. The promoter directed the expression of a gene namedssgB, which is related to the sporulation-specific cell division genessgA. These genes, together with three others, constitute a new family of paralogous genes specific forStreptomyces. S1-nuclease mapping using RNA prepared from anEscherichia colistrain that expressesssgBunder the control of σF, and fromS. coelicolorA3(2) at various developmental stages, identified identical transcription start points in both strains, corresponding to the promoterssgBp. The promoter is developmentally regulated inS. coelicolor: it is induced at the time of aerial mycelium formation and is most active during sporulation. However, the level of thessgBtranscript was unaffected in asigFmutant ofS. coelicolorA3(2). Interestingly, the level of the transcript was substantially reduced in anS. coelicolorstrain that was mutant for thesigHgene, which encodes a stress-response sigma factor (σH) that is essential for sporulation inS. coelicolorA3(2). This dependence ofssgBuponsigHwas confirmed by an in vitro transcription assay, in which σH, in the presence of theS. coelicolorcore RNA polymerase, was able to recognizessgBp. These results suggest that theS. coelicolor ssgBgene is under the control of the stress-response σH. Transcription ofssgBwas investigated inS. coelicolorA3(2) mutants with lesions in each of six known earlywhigenes required for sporulation septation. Expression ofssgBwas deregulated in three of the mutants (whiA,whiI, andwhiJ). Based on these data, it is proposed that thessgBgene product plays a role in the developmental process inS. coelicolorA3(2).