CLONES OF HUMAN RIBOSOMAL DNA CONTAINING THE COMPLETE 18 S-RIBOSOMAL-RNA AND 28 S-RIBOSOMAL-RNA GENES - CHARACTERIZATION, A DETAILED MAP OF THE HUMAN RIBOSOMAL TRANSCRIPTION UNIT AND DIVERSITY AMONG CLONES
CLONES OF HUMAN RIBOSOMAL DNA CONTAINING THE COMPLETE 18 S-RIBOSOMAL-RNA AND 28 S-RIBOSOMAL-RNA GENES - CHARACTERIZATION, A DETAILED MAP OF THE HUMAN RIBOSOMAL TRANSCRIPTION UNIT AND DIVERSITY AMONG CLONES
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DOI：
10.1042/bj2460519
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发表时间：
1987-09-01
影响因子：
4.1
通讯作者：
WAKEMAN, JA
中科院分区：
文献类型：
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作者：
MADEN, BEH;DENT, CL;WAKEMAN, JA
我们已经分离出几个新的人核糖体DNA克隆。每个克隆包含部分外部转录间隔区、完整的18 S-rRNA基因、内部转录间隔区、完整的28 S-rRNA基因和短的下游侧翼区。我们提出了一个详细的地图，人类核糖体转录单位与许多有用的限制性位点的位置。特别是，5.8 S-rRNA基因中的独特NheI位点使该基因能够相对于18 S-rRNA和28 S-rRNA基因进行定位。人类45 S-rRNA编码区约为13000个核苷酸残基长，其中外部转录间隔区包含约1000个核苷酸残基。第一和第二内转录间隔区包含约3700个核苷酸残基，1070和1200个核苷酸残基。对克隆间变异位点的部分调查揭示了18个S-rRNA基因序列之间的单点变异（第140位的T/C变异），18个S-rRNA基因侧翼转录间隔区的几个长度变异位点，以及28个S-rRNA基因之间的一些长度变异位点。这些变异位点大多与简单的层序域有关，并且位于已知经历相对快速的进化趋异的区域。特别是，28个S-rRNA基因之间的变异位点发生在G + C丰富的管道，其长度在脊椎动物中各不相同，可以与以前通过电子显微镜观察到的广泛的发夹结构相关。到目前为止，每一个经过详细调查的克隆体都在一个或多个方面与其他克隆体不同。
We have isolated several new clones of human ribosomal DNA. Each clone contains part of the external transcribed spacer, a complete 18 S-rRNA gene, the internal transcribed spacers, a complete 28 S-rRNA gene and a short downstream flanking region. We present a detailed map of the human ribosomal transcription unit with the locations of numerous useful restriction sites. In particular, a unique NheI site in the 5.8 S-rRNA gene enabled this gene to be mapped with respect to the 18 S-rRNA and 28 S-rRNA genes. The human 45 S-rRNA coding region is approx. 13 000 nucleotide residues long, of which the external transcribed spacer comprises approx. 3700 nucleotide residues and the first and second internal transcribed spacers comprise approx. 1070 and 1200 nucleotide residues respectively. A partial survey for sites of variation between clones has revealed a single point of variation among 18 S-rRNA gene sequences (a T/C variation at position 140), several sites of length variation in the regions of the transcribed spacers closely flanking the 18 S-rRNA genes, and some sites of length variation among 28 S-rRNA genes. Most of these sites of variation are associated with simple sequence tracts and are in regions that are known to undergo relatively rapid evolutionary divergence. In particular, the sites of variation among 28 S-rRNA genes occur in G + C-rich tracts whose lengths vary among vertebrates and that can be correlated with extensive hairpin structures previously observed by electron microscopy. Each of the clones so far surveyed in detail differs from the others in one or more respects.