Rodriguez J R, Pikielny C W, Rosbash M
Cell. 1984 Dec;39(3 Pt 2):603-10. doi: 10.1016/0092-8674(84)90467-7.
Yeast mRNA introns contain a conserved sequence, TACTAAC, required for splicing. We previously identified a putative splicing intermediate characterized by a stop to reverse transcriptase at the TACTAAC box of the wild-type rp51A (ribosomal protein 51A gene) intron. We now show that this stop is due to a branch and occurs at the identical nucleotide in the actin intron TACTAAC box. We show further that the putative intermediate contains a complete intron and the 3' exon, but is missing the 5' exon. This RNA is largely in the form of a lariat. The lariat and the other putative splicing intermediates detected (two forms, of different molecular weights, of the excised intron and the free 5' exon) are compatible with the view that the cut at the 5' junction and lariat formation are early steps in yeast mRNA splicing and that substantial similarities exist between yeast and mammalian mRNA splicing.
酵母信使核糖核酸内含子包含一个保守序列TACTAAC，这是剪接所必需的。我们之前鉴定出一种假定的剪接中间体，其特征是在野生型rp51A（核糖体蛋白51A基因）内含子的TACTAAC框处逆转录酶终止。我们现在表明，这种终止是由于分支的形成，并且发生在肌动蛋白内含子TACTAAC框中的相同核苷酸处。我们进一步表明，假定的中间体包含一个完整的内含子和3'外显子，但缺少5'外显子。这种核糖核酸主要呈套索状。套索状结构以及检测到的其他假定剪接中间体（切除的内含子和游离5'外显子的两种不同分子量形式）与以下观点相符：5'连接处的切割和套索状结构的形成是酵母信使核糖核酸剪接的早期步骤，并且酵母和哺乳动物信使核糖核酸剪接之间存在实质性相似之处。
