An Escherichia coli strain with all chromosomal rRNA operons inactivated:: Complete exchange of rRNA genes between bacteria
An Escherichia coli strain with all chromosomal rRNA operons inactivated:: Complete exchange of rRNA genes between bacteria
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DOI：
10.1073/pnas.96.5.1971
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发表时间：
1999-03-02
影响因子：
11.1
通讯作者：
Squires, CL
中科院分区：
文献类型：
--
作者：
Asai, T;Zaporojets, D;Squires, CL
目前的全球基因组学主要建立在rRNA序列上。然而，研究rRNA进化的实验系统并不容易获得，主要是因为rRNA基因在大多数实验生物中高度重复。我们已经构建了一个大肠杆菌菌株，其中所有7个染色体rRNA操纵子通过跨越16 S和23 S编码区的缺失而失活。一个E由多拷贝质粒携带的大肠杆菌rRNA操纵子向细胞提供16 S和23 S rRNA。通过使用该菌株，我们成功地创建了仅含有来自鼠伤寒沙门氏菌或普通变形杆菌的外源rRNA操纵子的微生物，这些微生物已经从大肠杆菌分化出来。大约1.2 - 3.5亿年前。我们也可以替换E。coli rRNA操纵子与E.大肠杆菌/酵母杂交的一个，其中GTdR中心关闭。coli 23 SrRNA已被酿酒酵母的相应结构域所取代。这些结果表明，与普遍的看法相反，rRNA与翻译机制中的许多其他组件的共同进化可能并不完全排除rRNA基因的水平转移。
Current global phylogenies are built predominantly on rRNA sequences. However, an experimental system for studying the evolution of rRNA is not readily available, mainly because the rRNA genes are highly repeated in most experimental organisms. We have constructed an Escherichia coli strain in which all seven chromosomal rRNA operons are inactivated by deletions spanning the 16S and 23S coding regions. A single E. coli rRNA operon carried by a multicopy plasmid supplies 16S and 23S rRNA to the cell. By using this strain we have succeeded in creating microorganisms that contain only a foreign rRNA operon derived from either Salmonella typhimurium or Proteus vulgaris, microorganisms that have diverged from E. coli about 120-350 million years ago. We also were able to replace the E. coli rRNA operon with an E. coli/yeast hybrid one in which the GTPase center off. coli 23S rRNA had been substituted by the corresponding domain from Saccharomyces cerevisiae. These results suggest that, contrary to common belief, coevolution of rRNA with many other components in the translational machinery may not completely preclude the horizontal transfer of rRNA genes.