Price J V
Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder 80309.
J Mol Biol. 1987 Jul 5;196(1):217-21. doi: 10.1016/0022-2836(87)90522-5.
The exons of the self-splicing pre-ribosomal RNA of Tetrahymena thermophila are joined accurately in vitro, even when only 33 nucleotides of the natural 5' exon and 38 nucleotides of the natural 3' exon remain. RNA fingerprint analysis was used to identify the unique ribonuclease T1 oligonucleotide generated by exon ligation. Secondary digests of the ligation junction oligonucleotide with ribonuclease A confirmed the identity of the fragment and demonstrated that the phosphate group that forms the phosphodiester bond at the ligation junction is derived from the 5' position of a uridine nucleotide in the RNA. This observation supports the prediction that the splice junction phosphate is derived from the 3' splice site. These results emphasize the mechanistic similarities of RNA splicing reactions of the group I introns, group II introns and nuclear pre-mRNA introns.
嗜热四膜虫自我剪接的前核糖体RNA的外显子在体外能够精确连接，即便天然5'外显子仅剩下33个核苷酸，天然3'外显子仅剩下38个核苷酸。RNA指纹分析被用于鉴定外显子连接产生的独特核糖核酸酶T1寡核苷酸。用核糖核酸酶A对连接位点寡核苷酸进行二次酶切，证实了该片段的身份，并表明在连接位点形成磷酸二酯键的磷酸基团源自RNA中尿苷酸的5'位。这一观察结果支持了剪接连接磷酸基团源自3'剪接位点的预测。这些结果强调了I类内含子、II类内含子和核前体mRNA内含子的RNA剪接反应在机制上的相似性。
