Stange N, Beier D, Beier H
Institut für Biochemie, Bayerische Julius-Maximilians-Universität, Würzburg, Germany.
Plant Mol Biol. 1991 May;16(5):865-75. doi: 10.1007/BF00015078.
The transcription of thirteen Arabidopsis tRNA(Tyr) genes in a tRNA gene cluster was studied in HeLa cell nuclear extracts. All tRNA(Tyr) genes are efficiently transcribed. Initiation of transcription starts at adenosine residues at positions -5 or -6, and termination occurs at an oligo(T) stretch located 17 to 21 bp downstream of the 3' end of the structural genes depending on the gene studied. Maturation of intron-containing pre-tRNAs was compared in HeLa cell and wheat germ extracts and revealed that 5' and 3' end processing precedes splicing in both systems. Two pre-tRNAs which carry mutations in the mature domain are not processed at all in the HeLa extract, whereas one of them matures with low efficiency in the wheat germ extract. The thirteen pre-tRNAs(Tyr) possess highly conserved intron sequences of 12 nucleotides. Twelve of these introns are efficiently excised, whereas one is removed at a reduced rate, possibly due to a slightly destabilized extended anticodon stem.
在HeLa细胞核提取物中研究了拟南芥tRNA（Tyr）基因簇中13个tRNA（Tyr）基因的转录情况。所有tRNA（Tyr）基因均能高效转录。转录起始于-5或-6位的腺苷残基，根据所研究的基因不同，转录终止于结构基因3'端下游17至21 bp处的一段寡聚（T）序列。对HeLa细胞和小麦胚芽提取物中含内含子的前体tRNA的成熟过程进行了比较，结果表明在这两个系统中，5'和3'端加工均先于剪接过程。在HeLa提取物中，两个在成熟结构域携带突变的前体tRNA根本无法进行加工，而其中一个在小麦胚芽提取物中成熟效率较低。这13个前体tRNA（Tyr）具有高度保守的12个核苷酸的内含子序列。其中12个内含子能有效切除，而有一个切除速率降低，可能是由于延伸的反密码子茎稍微不稳定所致。
