Yeast U1 snRNP-pre-mRNA complex formation without U1snRNA-pre-mRNA base pairing
Yeast U1 snRNP-pre-mRNA complex formation without U1snRNA-pre-mRNA base pairing
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DOI：
10.1017/s1355838201001844
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发表时间：
2001-01-01
期刊：
影响因子：
4.5
通讯作者：
Rosbash, M
中科院分区：
文献类型：
--
作者：
Du, H;Rosbash, M
U1 snRNA 的 5' 末端和前体 mRNA 的保守 5' 剪接位点之间的碱基配对对于体外定型复合物的形成非常重要。然而，前体 mRNA 最初被剪接机制识别的生化机制尚不清楚。为了评估这种碱基配对相互作用的作用，我们截短了U1 snRNA以消除RNA-RNA相互作用，并令人惊讶地发现U1 snRNP仍然可以形成几乎正常的RNA-蛋白质复合物并保持序列特异性。我们提出，Ut snRNP 的某些特征（可能是一种或多种蛋白质因子）比初始 5' 剪接位点识别的碱基配对更重要。此外，至少五组相互作用有助于复合物的形成或稳定性。其中只有一个是 U1 snRNA 5' 剪接位点和 5' 末端之间的碱基配对，没有碱基配对，U1 snRNP-pre-mRNA 复合物稳定性较差，并且构象略有改变。
Base pairing between the 5' end of U1 snRNA and the conserved 5' splice site of pre-mRNA is important for commitment complex formation in vitro. However, the biochemical mechanisms by which pre-mRNA is initially recognized by the splicing machinery is not well understood. To evaluate the role of this base pairing interaction, we truncated U1 snRNA to eliminate the RNA-RNA interaction and surprisingly found that U1 snRNP can still form a nearly normal RNA-protein complex and maintain sequence specificity. We propose that some feature of Ut snRNP, perhaps one or more protein factors, is more important than the base pairing for initial 5' splice site recognition. In addition, at least five sets of interactions contribute to complex formation or stability. Only one of these is base pairing between the 5' splice site and the 5' end of U1 snRNA, without which the U1 snRNP-pre-mRNA complex is less stable and has a somewhat altered conformation.