Global control of cysteine metabolism by CymR in Bacillus subtilis
Global control of cysteine metabolism by CymR in Bacillus subtilis
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DOI：
10.1128/jb.188.6.2184-2197.2006
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发表时间：
2006-03-01
影响因子：
3.2
通讯作者：
Martin-Verstraete, I
中科院分区：
文献类型：
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作者：
Even, S;Burguière, P;Martin-Verstraete, I
YrzC 先前已被鉴定为通过调节枯草芽孢杆菌中 YtII 激活剂合成来控制 ytmI 表达的阻遏蛋白。我们确定 YrzC 是硫代谢的主要调节因子。比较了在以硫酸盐作为唯一硫源的基本培养基中生长的枯草芽孢杆菌 Delta yrzC 突变体和野生型菌株的基因表达谱。在突变体中，观察到 24 个先前被鉴定为在硫酸盐存在下受到抑制的基因的表达增加。由于发现了几个参与导致半胱氨酸形成途径的基因，我们建议将 YrzC CymR 重命名为“半胱氨酸代谢阻遏物”。使用凝胶迁移实验证明了与 ytlI、ssuB、tcyP、yrrT、yxeK、cysK 或 ydbM 基因启动子区域的 CymR 依赖性结合。在这些基因的启动子区域发现了一个潜在的 CymR 靶位点 TAAWNCN(2)ANTWNAN(3)ATMGGAA TTW。在 DNase 足迹实验中，ytlI 启动子区域中的受保护区域包含此共有序列。该序列中的部分缺失或点突变的引入证实了其参与 ytlI、yrrT 和 yxeK 调节。在凝胶迁移实验中添加 O-乙酰丝氨酸可防止所有表征靶点依赖 CymR 与 DNA 结合。对 Delta cymR 突变体和野生型菌株的转录组分析也发现，与应激反应或向厌氧过渡相关的大量基因的表达水平发生了显着变化。
YrzC has previously been identified as a repressor controlling ytmI expression via its regulation of YtII activator synthesis in Bacillus subtilis. We identified YrzC as a master regulator of sulfur metabolism. Gene expression profiles of B. subtilis Delta yrzC mutant and wild-type strains grown in minimal medium with sulfate as the sole sulfur source were compared. In the mutant, increased expression was observed for 24 genes previously identified as repressed in the presence of sulfate. Since several genes involved in the pathways leading to cysteine formation were found, we propose to rename YrzC CymR, for "cysteine metabolism repressor." A CymR-dependent binding to the promoter region of the ytlI, ssuB, tcyP, yrrT, yxeK, cysK, or ydbM gene was demonstrated using gel shift experiments. A potential CymR target site, TAAWNCN(2)ANTWNAN(3)ATMGGAA TTW, was found in the promoter region of these genes. In a DNase footprint experiment, the protected region in the ytlI promoter region contained this consensus sequence. Partial deletion or introduction of point mutations in this sequence confirmed its involvement in ytlI, yrrT, and yxeK regulation. The addition of O-acetylserine in gel shift experiments prevented CymR-dependent binding to DNA for all of the targets characterized. Transcriptome analysis of a Delta cymR mutant and the wild-type strain also brought out significant changes in the expression level of a large set of genes related to stress response or to transition toward anaerobiosis.