Gallinaro H, Sittler A, Jacob M
Nucleic Acids Res. 1986 May 27;14(10):4171-85. doi: 10.1093/nar/14.10.4171.
To elucidate the function of hnRNP in the splicing of premRNA, we studied the distribution of the transcripts from the early region 3 of adenovirus-2 in hnRNP from infected HeLa cells. In addition to premRNAs and mRNAs, we detected excised IVS 1 and the products of cleavage of premRNA at the 5' splice site of IVS 1 (free leader 1 and IVS 1-exon 2). All these molecules were present in hnRNP and persisted in the salt-resistant complexes after a 400 mM KCl treatment. None of them was exclusively part of the salt dissociable monoparticles. The precursors, intermediates and products of the splicing reaction were associated with both monoparticles and salt resistant complexes. This eliminates the possibility that one of the classes of RNP is exclusively involved in one of the steps of RNA processing. Whereas the size of hnRNP was related to that of its RNA for most molecules, the small molecules free leader 1 and excised IVS 1 were found in the large hnRNP containing premRNA as well as in small size hnRNP. A probable interpretation of these results is that the cleavage products are associated with the premRNP complex immediately after cleavage and are then released in the form of an individual RNP.
为阐明核不均一核糖核蛋白（hnRNP）在mRNA前体剪接中的功能，我们研究了腺病毒2型早期区域3转录本在感染的HeLa细胞hnRNP中的分布。除了mRNA前体和mRNA外，我们还检测到切除的IVS 1以及mRNA前体在IVS 1的5'剪接位点处的切割产物（游离前导序列1和IVS 1 - 外显子2）。所有这些分子都存在于hnRNP中，并且在400 mM KCl处理后仍存在于耐盐复合物中。它们中没有一个是盐可解离单颗粒的唯一组成部分。剪接反应的前体、中间体和产物与单颗粒和耐盐复合物都有关联。这排除了某一类核糖核蛋白（RNP）专门参与RNA加工步骤之一的可能性。虽然对于大多数分子来说，hnRNP的大小与其RNA的大小相关，但小分子游离前导序列1和切除的IVS 1既存在于含有mRNA前体的大型hnRNP中，也存在于小型hnRNP中。这些结果的一个可能解释是，切割产物在切割后立即与mRNA前体核糖核蛋白复合物相关联，然后以单个核糖核蛋白的形式释放。
