Wawrousek E F, Hansen J N
J Biol Chem. 1983 Jan 10;258(1):291-8.
Hybridization of Southern blots of EcoRI digests of total Bacillus subtilis DNA with ribosomal RNA and transfer RNA probes provides evidence of highly clustered tRNA and rRNA genes, with several tRNA clusters being located in spaces which span between tandem ribosomal RNA gene sets. Clones containing these tRNA clusters were isolated from a Charon 4A library. One of them, denoted trrnB, was partially sequenced. A cluster of six tRNA genes was found, with anticodon assignments of Asn, Thr, Gly, Arg, Pro, Ala. This cluster is closely flanked on both sides by ribosomal RNA gene sets, which were identified by sequencing upward through the 5 S rRNA gene, across a space, and into the 23 S rRNA gene, and also sequencing downward into the 16 S rRNA gene. The tRNA gene cluster appears to be organized into at least two transcriptional units separated by an attenuator region. These transcriptional units may be components of the flanking ribosomal RNA operons. The putative promoter region of the downstream 16 S rRNA is organized differently from Escherichia coli; it is smaller and seems less complex. This gene organization provides insight into possible mechanisms for coordinate and differential control of transfer and ribosomal RNA gene expression.
用核糖体RNA和转运RNA探针与枯草芽孢杆菌总DNA的EcoRI酶切片段进行Southern杂交，结果表明tRNA和rRNA基因高度聚集，几个tRNA簇位于串联核糖体RNA基因集之间的间隔区域。从Charon 4A文库中分离出了含有这些tRNA簇的克隆。其中一个命名为trrnB的克隆进行了部分测序。发现了一个由六个tRNA基因组成的簇，其反密码子分别对应天冬酰胺、苏氨酸、甘氨酸、精氨酸、脯氨酸和丙氨酸。该簇两侧紧密排列着核糖体RNA基因集，通过对5S rRNA基因向上测序、跨越一段间隔区域并进入23S rRNA基因，以及向下测序进入16S rRNA基因来确定这些基因集。tRNA基因簇似乎被组织成至少两个由一个间隔区域隔开的转录单元。这些转录单元可能是侧翼核糖体RNA操纵子的组成部分。下游16S rRNA的假定启动子区域的组织方式与大肠杆菌不同；它更小且似乎不太复杂。这种基因组织方式为研究转运RNA和核糖体RNA基因表达的协同和差异控制的可能机制提供了线索。
