Base pairing with U6atac snRNA is required for 5′ splice site activation of U12-dependent introns in vivo
Base pairing with U6atac snRNA is required for 5′ splice site activation of U12-dependent introns in vivo
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DOI：
10.1017/s1355838298980207
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发表时间：
1998-06-01
期刊：
影响因子：
4.5
通讯作者：
Padgett, RA
中科院分区：
文献类型：
--
作者：
Incorvaia, R;Padgett, RA
较小的 U12 依赖性真核细胞核前 mRNA 内含子通过独特的剪接体机制进行剪接，该机制需要 U11、U12、U5、U4atac 和 U6atac snRNA 的功能。先前的工作表明，U11 snRNA 通过与保守的 5' 剪接位点序列碱基配对而发挥作用，与主要类剪接体中的 U1 snRNA 类似。在这里，我们表明 U6atac snRNA 也以类似于主要类剪接体中 U6 snRNA 的方式与 5' 剪接位点碱基配对。我们表明，通过补偿性 U6atac snRNA 突变体的共表达，可以激活 5' 剪接位点的剪接缺陷突变体进行体内剪接。在某些情况下，剪接的最大恢复需要补偿性 U11 snRNA 突变体的共表达。突变表型抑制的等位基因特异性与 pre-mRNA 和 snRNA 之间的 Watson-Crick 碱基配对一致。这些结果为 U12 依赖性剪接体核心的 RNA-RNA 相互作用模型提供了支持，该模型与主要类 U2 依赖性剪接体的模型惊人地相似。
The minor U12-dependent class of eukaryotic nuclear pre-mRNA introns is spliced by a distinct spliceosomal mechanism that requires the function of U11, U12, U5, U4atac, and U6atac snRNAs. Previous work has shown that U11 snRNA plays a role;similar to U1 snRNA in the major class spliceosome by base pairing to the conserved 5' splice site sequence. Here we show that U6atac snRNA also base pairs to the 5' splice site in a manner analogous to that of U6 snRNA in the major class spliceosome. We show that splicing defective mutants of the 5' splice site can be activated for splicing in vivo by the coexpression of compensatory U6atac snRNA mutants. In some cases, maximal restoration of splicing required the coexpression of compensatory U11 snRNA mutants. The allelic specificity of mutant phenotype suppression is consistent with Watson-Crick base pairing between the pre-mRNA and the snRNAs. These results provide support for a model of the RNA-RNA interactions at the core of the U12-dependent spliceosome that is strikingly similar to that of the major class U2-dependent spliceosome.