英国邓迪大学研究人员通过分析大肠杆菌基因组新发现三个大肠杆菌生长发育必需基因，其中一个基因也在人体中发现，与癌症发生密切相关。
研究人员将新发现的三个基因命名为：yjeE, yeaZ和ygjD。实验证明三个基因与大肠杆菌正常生长发育密切相关，限制yeaZ基因表达会使大肠杆菌细胞核区高度浓缩，限制yjeE和ygjD基因表达则导致DNA在细胞中分配不均。
研究人员还发现ygjD基因也出现在人类基因组中，是新发现的三个基因中最重要的一个
Department of Molecular Microbiology, John Innes Centre, Colney Lane, Norwich NR4 7UH, United Kingdom,1 School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom,2 Division of Molecular and Environmental Microbiology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom,3 Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California, 94720,4 Banting and Best Department of Medical Research, Terrence Donnelly Center for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada M5S 3E15
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.
