Economidis I V, Pederson T
Proc Natl Acad Sci U S A. 1983 Mar;80(6):1599-602. doi: 10.1073/pnas.80.6.1599.
Mouse erythroleukemia cells were pulse-labeled with [3H]uridine and irradiated with 254-nm light to produce covalent crosslinks between RNA and proteins in close proximity to one another in vivo. Nuclear ribonucleoprotein particles containing heterogeneous nuclear RNA were isolated and digested with nucleases, and the resulting proteins were subjected to gel electrophoresis. Proteins carrying covalently crosslinked [3H]uridine nucleotides were identified by fluorography. The results demonstrate that heterogeneous nuclear RNA is complexed in vivo with a set of six major proteins having molecular weights between 32,500 and 41,500. Analysis of chromatin fractions indicates that nascent heterogeneous nuclear RNA chains assemble with these six proteins as a very early post-transcriptional event. These data, and other results [Nevins, J. R. & Darnell, J. E. (1981) Cell 15, 1477-1493], lead us to propose the usual order of post-transcriptional events to be: heterogeneous nuclear RNA-ribonucleoprotein particle assembly leads to poly(A) addition leads to splicing.
用[3H]尿苷对小鼠红白血病细胞进行脉冲标记，并用254纳米的光照射，以在体内使彼此紧邻的RNA和蛋白质之间形成共价交联。分离出含有不均一核RNA的核糖核蛋白颗粒，并用核酸酶消化，然后将所得蛋白质进行凝胶电泳。通过荧光自显影鉴定携带共价交联的[3H]尿苷核苷酸的蛋白质。结果表明，不均一核RNA在体内与一组分子量在32,500至41,500之间的六种主要蛋白质形成复合物。染色质组分分析表明，新生的不均一核RNA链与这六种蛋白质组装是转录后非常早期的事件。这些数据以及其他结果[内文斯，J.R.和达内尔，J.E.（1981年）《细胞》15卷，1477 - 1493页]，使我们提出转录后事件的通常顺序为：不均一核RNA - 核糖核蛋白颗粒组装导致聚腺苷酸化导致剪接。
