Sox transcription in sarcosine utilization is controlled by Sigma(54) and SoxR in Bacillus thuringiensis HD73.
Sox transcription in sarcosine utilization is controlled by Sigma(54) and SoxR in Bacillus thuringiensis HD73.
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DOI：
10.1038/srep29141
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发表时间：
2016-07-12
影响因子：
4.6
通讯作者：
Song F
中科院分区：
文献类型：
--
作者：
Peng Q;Liu C;Wang B;Yang M;Wu J;Zhang J;Song F
肌氨酸氧化酶催化肌氨酸的氧化去甲基化以产生甘氨酸、甲醛和过氧化氢。本研究分析了苏云金芽孢杆菌（Bacillus thuringiensis，Bt）中sox基因的转录和调控，包括肌氨酸氧化酶编码基因。RT-PCR分析表明，sox基因座形成两个相对的转录单位：soxB（soxB/E/F/G/H/I）和soxR（soxR/C/D/A）。典型的-12/-24共有序列分别位于soxB和soxC的转录起始位点（TSS）的15 bp和12 bp处。启动子-lacZ融合分析表明，soxB启动子由Sigma 54因子控制，并由Sigma 54依赖性转录调节因子SoxR激活。SoxR也抑制其自身的表达。从负责soxC、soxD和soxA转录的PsoxCR启动子的表达是Sigma 54依赖性的，并且需要SoxR。一个11 bp的反向重复序列被确定为SoxR结合位点上游的soxB TSS。纯化的SoxR特异性结合含有该区域的DNA片段。该序列的突变或缺失废除了soxB和soxC的转录活性。因此，SoxR结合到相同的序列以激活soxB和soxC的转录。肌氨酸的利用被取消在soxB和soxR突变体，这表明Sox基因座是必不可少的肌氨酸利用。
Sarcosine oxidase catalyzes the oxidative demethylation of sarcosine to yield glycine, formaldehyde, and hydrogen peroxide. In this study, we analyzed the transcription and regulation of the sox locus, including the sarcosine oxidase-encoding genes in Bacillus thuringiensis (Bt). RT-PCR analysis revealed that the sox locus forms two opposing transcriptional units: soxB (soxB/E/F/G/H/I) and soxR (soxR/C/D/A). The typical −12/−24 consensus sequence was located 15 bp and 12 bp from the transcriptional start site (TSS) of soxB and soxC, respectively. Promoter-lacZ fusion assays showed that the soxB promoter is controlled by the Sigma54 factor and is activated by the Sigma54-dependent transcriptional regulator SoxR. SoxR also inhibits its own expression. Expression from the PsoxCR promoter, which is responsible for the transcription of soxC, soxD, and soxA, is Sigma54-dependent and requires SoxR. An 11-bp inverted repeat sequence was identified as SoxR binding site upstream of the soxB TSS. Purified SoxR specifically bound a DNA fragment containing this region. Mutation or deletion of this sequence abolished the transcriptional activities of soxB and soxC. Thus, SoxR binds to the same sequence to activate the transcription of soxB and soxC. Sarcosine utilization was abolished in soxB and soxR mutants, suggesting that the sox locus is essential for sarcosine utilization.