Sutton R E, Boothroyd J C
Cell. 1986 Nov 21;47(4):527-35. doi: 10.1016/0092-8674(86)90617-3.
The 5' ends of trypanosome mRNAs consist of an identical sequence of 35 nucleotides. This "mini-exon" sequence is derived from the 5' end of a 137 nucleotide RNA (medRNA). The remainder of each mRNA is derived from a protein-coding exon that is not linked to the mini-exon. We propose that medRNA is spliced in trans to de-novo-initiated transcripts of protein-coding genes. This trans splicing model predicts that the downstream portion of medRNA will be part of a branched structure and then be released as a free product (minRNA). We demonstrate that significant levels of minRNA exist in trypanosome RNA. Furthermore, minRNA can be released from high molecular weight RNA by a HeLa cell S100 "debranching" extract. We conclude that trans splicing is the physiological process by which mature mRNA molecules are synthesized in trypanosomes.
锥虫mRNA的5'端由35个核苷酸的相同序列组成。这个“微型外显子”序列来自于一个137个核苷酸RNA（medRNA）的5'端。每个mRNA的其余部分来自于一个与微型外显子不相连的蛋白质编码外显子。我们提出，medRNA通过反式剪接与蛋白质编码基因的从头起始转录本结合。这个反式剪接模型预测，medRNA的下游部分将成为分支结构的一部分，然后作为游离产物（minRNA）释放出来。我们证明，锥虫RNA中存在大量的minRNA。此外，minRNA可以通过HeLa细胞S100“去分支”提取物从高分子量RNA中释放出来。我们得出结论，反式剪接是锥虫中合成成熟mRNA分子的生理过程。
