Giroux S, Beaudet J, Cedergren R
Département de Biochimie, Université de Montréal, Québec, Canada.
J Bacteriol. 1988 Dec;170(12):5601-6. doi: 10.1128/jb.170.12.5601-5606.1988.
A DNA fragment comprising the four tRNA gene sequences of the Escherichia coli argT locus hybridized with two Sau3A-generated DNA fragments from the vibrio Photobacterium phosphoreum (ATCC 11040). Detailed sequence analysis of the longer fragment shows the following gene organization: 5'-promoter-tRNA(Pro)-tRNAPro-tRNA(Pro)-tRNA(His)-tRNA(Pro)-tRNA(Pro)- tRNA(His)-tRNA(Pro)-five pseudogenes derived from the upstream tRNAPro interspersed by putative Rho-independent terminators. This sequence demonstrates the presence of highly repetitive, tandem tRNA genes in a bacterial genome. Furthermore, a stretch of 304 nucleotides from this cluster was found virtually unchanged in the other (shorter) fragment which was previously sequenced. The two clusters together contain eight tRNA(Pro) pseudogenes and eight fully intact tRNA(Pro) genes, an unusually high number for a single eubacterial isoacceptor tRNA. These results show that the organization of some tRNA operons is highly variable in eubacteria.
一个包含大肠杆菌argT基因座四个tRNA基因序列的DNA片段,与来自磷光弧菌(ATCC 11040)的两个Sau3A酶切产生的DNA片段杂交。对较长片段的详细序列分析显示了以下基因组织:5'-启动子-tRNA(Pro)-tRNAPro-tRNA(Pro)-tRNA(His)-tRNA(Pro)-tRNA(Pro)-tRNA(His)-tRNA(Pro)-五个源自上游tRNAPro的假基因,其间穿插着假定的不依赖Rho的终止子。该序列证明了细菌基因组中存在高度重复的串联tRNA基因。此外,在先前测序的另一个(较短)片段中发现,来自该簇的一段304个核苷酸的序列几乎没有变化。这两个簇总共包含八个tRNA(Pro)假基因和八个完全完整的tRNA(Pro)基因,对于单个真细菌同功受体tRNA来说,这个数量异常高。这些结果表明,真细菌中一些tRNA操纵子的组织具有高度变异性。