Conserved Network of Proteins Essential for Bacterial Viability
Conserved Network of Proteins Essential for Bacterial Viability
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DOI：
10.1128/jb.00136-09
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发表时间：
2009-08-01
影响因子：
3.2
通讯作者：
Palmer, Tracy
中科院分区：
文献类型：
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作者：
Handford, Jennifer I.;Ize, Berengere;Palmer, Tracy
YJEE，YEAZ和YGJD基因在Eubacteria的基因组中高度保守，并且在整个古细菌和真核生物中也发现了YGJD直系同源物。在这项研究中，我们在模型生物体大肠杆菌K12中为每个基因构建了条件表达菌株。我们表明，每个基因对于在实验室生长条件下大肠杆菌的生存能力至关重要。在非验证条件下有条件菌株的生长导致细胞超微结构的巨大变化。故意抑制YEAZ的表达会导致具有高度凝结核苷的细胞，而YJEE和YGJD表达的抑制至少导致至少一定比例的非常肿大的细胞，而DNA的外周分布异常。三种条件表达菌株中的每一个都可以通过带有RSTA基因的多拷贝克隆进行补充，该基因编码了两个组件系统响应调节剂，强烈表明这些蛋白质与同一必需的细胞途径有关。细菌两杂交实验的结果表明，Yeaz可以与YJEE和YGJD相互作用，但YGJD是首选的相互作用伴侣。体外实验的结果表明，Yeaz介导了YGJD的蛋白水解，这表明Yeaz和Yjee是控制该蛋白活性的调节剂。我们的结果与这些蛋白质一致，这些蛋白质形成了DNA代谢与细胞分裂之间的联系。
The yjeE, yeaZ, and ygjD genes are highly conserved in the genomes of eubacteria, and ygjD orthologs are also found throughout the Archaea and eukaryotes. In this study, we have constructed conditional expression strains for each of these genes in the model organism Escherichia coli K12. We show that each gene is essential for the viability of E. coli under laboratory growth conditions. Growth of the conditional strains under nonpermissive conditions results in dramatic changes in cell ultrastructure. Deliberate repression of the expression of yeaZ results in cells with highly condensed nucleoids, while repression of yjeE and ygjD expression results in at least a proportion of very enlarged cells with an unusual peripheral distribution of DNA. Each of the three conditional expression strains can be complemented by multicopy clones harboring the rstA gene, which encodes a two-component-system response regulator, strongly suggesting that these proteins are involved in the same essential cellular pathway. The results of bacterial two-hybrid experiments show that YeaZ can interact with both YjeE and YgjD but that YgjD is the preferred interaction partner. The results of in vitro experiments indicate that YeaZ mediates the proteolysis of YgjD, suggesting that YeaZ and YjeE act as regulators to control the activity of this protein. Our results are consistent with these proteins forming a link between DNA metabolism and cell division.