Kato Jun-ichi, Hashimoto Masayuki
Department of Biological Sciences, Graduate Schools of Science and Engineering, Tokyo Metropolitan University, Minamiohsawa, Hachioji, Tokyo, Japan.
Mol Syst Biol. 2007;3:132. doi: 10.1038/msb4100174. Epub 2007 Aug 14.
The minimal set of genetic information necessary and sufficient to sustain a functioning cell contains not only trans-acting genes, but also cis-acting chromosomal regions that cannot be complemented by plasmids carrying these regions. In Escherichia coli (E. coli), only one chromosomal region, the origin of replication has been identified to be cis-acting. We constructed a series of mutants with long-range deletions, and the chromosomal regions containing trans-acting essential genes were deleted in the presence of plasmids complementing the deleted genes. The deleted regions cover all regions of the chromosome except for the origin and terminus of replication. The terminus affects cell growth, but is not essential. Our results indicate that the origin of DNA replication is the only vital, unique cis-acting DNA sequence in the E. coli chromosome necessary for survival.
维持一个功能正常的细胞所必需且足够的最小遗传信息集不仅包含反式作用基因，还包含顺式作用染色体区域，这些区域不能被携带这些区域的质粒所互补。在大肠杆菌中，只有一个染色体区域，即复制起点，已被确定为顺式作用区域。我们构建了一系列具有长程缺失的突变体，并且在互补缺失基因的质粒存在的情况下，删除了包含反式作用必需基因的染色体区域。删除的区域覆盖了染色体除复制起点和终点之外的所有区域。终点影响细胞生长，但并非必需。我们的结果表明，DNA复制起点是大肠杆菌染色体中生存所必需的唯一至关重要且独特的顺式作用DNA序列。
