Association with terminal exons in pre-mRNAs: a new role for the U1 snRNP?
Association with terminal exons in pre-mRNAs: a new role for the U1 snRNP?
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DOI：
10.1101/gad.7.4.647
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发表时间：
1993-04
影响因子：
10.5
通讯作者：
K. M. Wassarman;J. Steitz
中科院分区：
文献类型：
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作者：
K. M. Wassarman;J. Steitz
补骨脂素在HeLa细胞核抽提物中的交联实验表明，U1单链RNA与含有SV40晚期和腺病毒L3多腺化信号的底物结合。U1与底物的交联点将AAUAAA序列上游不同距离的区域映射到U1 SnRNA 5‘端的有限互补区。通过上游3‘剪接位点的增加，U1与SV40晚期Pre-mRNA中的同一位点的交联性增强，这也增强了多聚腺苷化。对不同核提取物的研究表明，U1交联与剪接和多聚腺苷基化的耦合之间存在相关性，表明U1 SnRNP参与了这两个RNA加工事件的协调。突变分析表明，U1/底物结合不会太强，不足以发生偶联，并表明U1 SnRNP在识别内部和3‘端外显子方面起着类似的作用。讨论了剪接和多聚腺苷酸化机制之间可能的通讯机制，以及U1 SnRNP与3‘末端外显子的相互作用如何有助于mRNA输出。
Psoralen cross-linking experiments in HeLa cell nuclear extracts have revealed the binding of U1 snRNA to substrates containing the SV40 late and adenovirus L3 polyadenylation signals. The sites of U1 cross-linking to the substrates map different distances upstream of the AAUAAA sequence to regions with limited complementarity to the 5' end of U1 snRNA. U1 cross-linking to the same site in the SV40 late pre-mRNA is enhanced by the addition of an upstream 3' splice site, which also enhances polyadenylation. Examination of different nuclear extracts reveals a correlation between U1 cross-linking and the coupling of splicing and polyadenylation, suggesting that the U1 snRNP participates in the coordination of these two RNA-processing events. Mutational analyses demonstrate that U1/substrate association cannot be too strong for coupling to occur and suggest that the U1 snRNP plays a similar role in recognition of internal and 3' terminal exons. Possible mechanisms for communication between the splicing and polyadenylation machineries are discussed, as well as how interaction of the U1 snRNP with 3' terminal exons might contribute to mRNA export.