A SET OF TRANSFER-RNAS THAT LACK EITHER THE T-PSI-C ARM OR THE DIHYDROURIDINE ARM - TOWARDS A MINIMAL TRANSFER-RNA ADAPTER
A SET OF TRANSFER-RNAS THAT LACK EITHER THE T-PSI-C ARM OR THE DIHYDROURIDINE ARM - TOWARDS A MINIMAL TRANSFER-RNA ADAPTER
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DOI：
10.1002/j.1460-2075.1990.tb07542.x
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发表时间：
1990-10-01
期刊：
影响因子：
11.4
通讯作者：
WOLSTENHOLME, DR
中科院分区：
文献类型：
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作者：
OKIMOTO, R;WOLSTENHOLME, DR
线虫、秀丽隐杆线虫和猪蛔虫的线粒体DNA （mtDNA）分子含有22个非标准形式trna的假定基因。推断的转录本可以折叠成20个独立的结构，每个结构类似于tRNA，其t . psic臂和可变环被6-12个核苷酸的简单环所取代。在另外两种结构中[类似于ser（UCN）和ser（AGN）的trna]，二氢吡啶臂被5-8个核苷酸组成的环所取代。通过将mt-tRNA基因特异性寡核苷酸探针与线虫rna杂交，我们已经获得了至少9个秀丽隐杆线虫和3个隐杆线虫mt-tRNA基因转录的证据。每个转录本（tRNA）都是根据各自的DNA序列预测的精确大小，转录后添加了三个核苷酸，可能是CCA。一个例外是秀丽隐杆线虫的mt-tRNAasn，它的大多数分子比基因预测的多一个核苷酸（加上CCA）。这些数据有力地支持了线虫的功能性mt-tRNA是结构异常的mt-tRNA基因的直接转录本（仅添加CCA）的结论。没有证据表明通过反式剪接或RNA编辑来添加这些非标准trna中缺失的序列。因此，我们推测非标准形式在线粒体蛋白质合成中是活跃的。
The mitochondrial DNA (mtDNA) molecules of the nematode worms, Caenorhabditis elegans and Ascaris suum contain 22 putative genes for non-standard forms of tRNAs. The inferred transcripts can be folded into 20 separate structures each resembling a tRNA whose T.psi.C arm and variable loop are replaced with a simple loop of 6-12 nucleotides. In two further structures [that resemble tRNAs for ser(UCN) and ser(AGN)], the dihydrouridine arm is replaced by a loop of 5-8 nucleotides. By hybridizing mt-tRNA gene-specific oligonucleotide probes to nematode RNAs, we have obtained evidence for transcription of at least nine C. elegans and three A. suum mt-tRNA genes. Each transcript (tRNA) is the exact size predicted from the respective DNA sequence, to which three nucleotides, presumably CCA, have been added following transcription. An exception was C. elegans mt-tRNAasn, most molecules of which had one nucleotide (plus CCA) more than predicted from the gene. The data presented strongly support the conclusion that the functional mt-tRNAs of nematode worms are direct transcripts (with only CCA addition) of the structurally unusual mt-tRNA genes. There is no evidence of trans-splicing or RNA editing to add the sequences missing from these nonstandard tRNAs. We presume, therefore, that the non-standard forms are active in mitochondrial protein synthesis.