The entericidin locus of Escherichia coli and its implications for programmed bacterial cell death
The entericidin locus of Escherichia coli and its implications for programmed bacterial cell death
复制标题
DOI：
10.1006/jmbi.1998.1894
复制
发表时间：
1998-07-24
影响因子：
5.6
通讯作者：
Weiner, JH
中科院分区：
文献类型：
--
作者：
Bishop, RE;Leskiw, BK;Weiner, JH
被称为“成瘾模块”的解毒剂/毒素基因对可以通过分离后杀死的方式在细菌群体中维持质粒。然而，几个染色体编码的成瘾模块可能提供一个完全不同的功能，在程序性细胞死亡的濒死亚群饥饿条件下。我们现在报告了一种新的大肠杆菌染色体溶菌模块，称为entericidin基因座，它在高渗透压条件下在稳定期被sigma（S）激活，同时被β调节EnvZ/OmpR信号转导途径抑制。肠毒素基因座编码串联旁系同源基因（ecnAB），并指导两个小细胞包膜脂蛋白的合成。衰减子在ecnA之前，并且ompR敏感的sigma（S）启动子控制ecnB的表达。肠毒素A脂蛋白是溶菌脂蛋白肠毒素B的解毒剂。预期肠杀菌素采用两亲性α-螺旋结构，并可调节膜稳定性。肠毒素基因座不存在于任何已知质粒上，但在弗氏柠檬酸杆菌染色体的同源区域中是保守的。虽然克隆的C. freundii entericidin基因座在E.在大肠杆菌中，它独立于ompR，携带一个额外的类似ompR的基因，称为ecnR。肠毒素基因座作为染色体解毒剂/毒素基因对的组织，其在饥饿期间受正和负渗透信号的调节，与程序性细菌细胞死亡的新兴范例一致。(C)北京：科学出版社.
Antidote/toxin gene pairs known as "addiction modules" can maintain plasmids in bacterial populations by means of post-segregational killing. However, several chromosome-encoded addiction modules may provide an entirely distinct function in the programmed cell death of moribund subpopulations under starvation conditions. We now report a novel chromosomal bacteriolytic module of Escherichia coli called the entericidin locus, which is activated in stationary phase under high osmolarity conditions by sigma(S) and simultaneously repressed by the osmoregulatory EnvZ/OmpR signal transduction pathway. The entericidin locus encodes tandem paralogous genes (ecnAB) and directs the synthesis of two small cell-envelope lipoproteins. An attenuator precedes ecnA and an ompR-sensitive sigma(S) promoter governs expression of ecnB. The entericidin A lipoprotein is an antidote to the bacteriolytic lipoprotein entericidin B. The entericidins are predicted to adopt amphipathic alpha-helical structures and to reciprocally modulate membrane stability. The entericidin locus is not present on any known plasmids, but is conserved in the homologous region of the Citrobacter freundii chromosome. Although the cloned C. freundii entericidin locus is expressed in E. coli independently of ompR, it carries an additional ompR-like gene called ecnR. The organization of the entericidin locus as a chromosomal antidote/toxin gene pair, which is regulated by both positive and negative osmotic signals during starvation, is consistent with an emerging paradigm of programmed bacterial cell death. (C) 1998 Academic Press.