Konforti B B, Konarska M M
Rockefeller University, New York, New York 10021, USA.
RNA. 1995 Oct;1(8):815-27.
A short 5' splice site RNA oligonucleotide (5'SS RNA oligo) undergoes both steps of splicing when a second RNA containing the 3' splice site region (3'SS RNA) is added in trans. This trans-splicing reaction displays the same 5' and 3' splice site sequence requirements as cis-splicing of full-length pre-mRNA. The analysis of RNA-snRNP complexes formed on each of the two splice site RNAs is consistent with the formation of partial complexes, which then associate to form the complete spliceosome. Specifically, U2 snRNP bound to the 3'SS RNA associates with U4/U5/U6 snRNP bound to the 5'SS RNA oligo. Thus, as expected, trans-splicing depends on the integrity of U2, U4, and U6 snRNAs. However, unlike cis-splicing, trans-splicing is enhanced when the 5' end of U1 snRNA is blocked or removed or when the U1 snRNP is depleted. Thus, the early regulatory requirement for U1 snRNP, which is essential in cis-splicing, is bypassed in this trans-splicing system. This simplified trans-splicing reaction offers a unique model system in which to study the mechanistic details of pre-mRNA splicing.
当添加一个包含3'剪接位点区域的第二条RNA（3'SS RNA）进行反式剪接时，一个短的5'剪接位点RNA寡核苷酸（5'SS RNA oligo）会经历剪接的两个步骤。这种反式剪接反应与全长前体mRNA的顺式剪接显示出相同的5'和3'剪接位点序列要求。对在两个剪接位点RNA上形成的RNA - snRNP复合物的分析与部分复合物的形成一致，然后这些部分复合物相互结合形成完整的剪接体。具体而言，与3'SS RNA结合的U2 snRNP与与5'SS RNA寡核苷酸结合的U4/U5/U6 snRNP相互作用。因此，正如预期的那样，反式剪接依赖于U2、U4和U6 snRNA的完整性。然而，与顺式剪接不同的是，当U1 snRNA的5'端被封闭或去除或者U1 snRNP被耗尽时，反式剪接会增强。因此，在这个反式剪接系统中，绕过了顺式剪接中必不可少的对U1 snRNP的早期调控要求。这种简化的反式剪接反应提供了一个独特的模型系统，用于研究前体mRNA剪接的机制细节。
