Mce2R from Mycobacterium tuberculosis represses the expression of the mce2 operon
Mce2R from Mycobacterium tuberculosis represses the expression of the mce2 operon
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DOI：
10.1016/j.tube.2008.09.002
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发表时间：
2009-01-01
期刊：
影响因子：
3.2
通讯作者：
Bigi, Fabiana
中科院分区：
文献类型：
--
作者：
de la Paz Santangelo, Maria;Blanco, Federico;Bigi, Fabiana
mce2 操纵子是结核分枝杆菌中存在的四种 mce 操纵子之一，它编码可能在该细菌的毒力机制中发挥作用的输出蛋白。在本研究中，我们证明 Rv0586 编码假定的 GntR 样调节因子，是 mce2 操纵子的一部分。通过使用启动子-lacZ 融合方法和生物信息学工具，我们发现 Rv0586 抑制 Mce2 蛋白和由末端 (Rv0670) 基因编码的推定核酸内切酶 IV 的表达。为此，我们将阻遏蛋白重新命名为 Mce2R。通过凝胶迁移实验，确定 Mce2R 结合位于 mce2 启动子区域内。此外，在 mce2 操纵子和末端基因的启动子区域内发现了两个类似 FadR 的操纵子基序。这些图案与假定的 -10 和 -35 指示符框重叠。携带 mce2 和末端启动子-lacZ 融合体的结核分枝杆菌被用来感染 J774 巨噬细胞样细胞。吞噬后诱导β-半乳糖苷酶表达，表明某些细胞因子可能是mce2操纵子分子开关调节表达的关键组成部分。总之，这些结果为 mce 操纵子表达的复杂调节提供了新的证据。 (C) 2008 Elsevier Ltd. 保留所有权利。
The mce2 operon is one of the four mce operons present in Mycobacterium tuberculosis that encode exported proteins with a probable role in the virulence mechanisms of this bacterium. In the present study we demonstrated that Rv0586, which encodes a putative GntR-like regulator, is part of the mce2 operon. By using a promoter-lacZ fusion approach and bioinformatics tools, we found that Rv0586 represses the expression of Mce2 proteins and of a putative endonuclease IV, encoded by end (Rv0670) gene. For this reason, we have re-named the repressor protein Mce2R. By gel-shift experiments Mce2R binding was determined to be located within the mce2 promoter region. In addition, two FadR-like operator motifs were identified within the promoter regions of both the mce2 operon and the end gene. These motifs overlap putative -10 and -35 prornoter boxes. M. tuberculosis carrying mce2 and end promoter-lacZ fusions were used to infect J774 macrophage-like cells. Expression of P-galactosidase was induced after phagocytocis, suggesting that some cellular factor could be a key component of the molecular switch regulation expression of the mce2 operon. In conclusion, these results add novel evidence of the complex regulation of mce operon expression. (C) 2008 Elsevier Ltd. All rights reserved.