Yeast Ntr1/Spp382 mediates Prp43 function in postspliceosomes
Yeast Ntr1/Spp382 mediates Prp43 function in postspliceosomes
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DOI：
10.1128/mcb.02347-05
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发表时间：
2006-08-01
影响因子：
5.3
通讯作者：
Beggs, Jean D.
中科院分区：
文献类型：
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作者：
Boon, Kum-Loong;Auchynnikava, Tatsiana;Beggs, Jean D.
酿酒酵母的Ntr1和Ntr2蛋白已被报道与参与前mRNA剪接的蛋白质相互作用，但它们在剪接过程中的作用尚不清楚。我们在这里表明，它们与一个包含被切除的内含子和剪接体U2、U5和U6 SnRNAs的剪接后复合体有关，支持与前mRNA剪接过程的后期阶段的联系。从代谢中耗尽NO的细胞中提取出来的剪接活性较低，并积累了被切除的内含子。此外，在Ntr1缺失的提取物中，U4/U6 di-SnRNP的水平增加，而游离的U5和U6 SnRNP的水平降低，并且U2的水平增加和U4的水平降低与U5 SnRNP蛋白Prp8相关。这些结果表明，Ntr1对于切除的内含子复合体的周转和SnRNPs的循环是必需的。Ntr1直接或间接地与内含子释放因子Prp43相互作用，是与被切除的内含子相关联所必需的。我们认为，Ntr1可能通过作为Prp43的剪接体受体或RNA靶向因子，在Ntr2蛋白的辅助下，促进剪接复合体中切除的内含子的释放。
The Ntr1 and Ntr2 proteins of Saccharomyces cerevisiae have been reported to interact with proteins involved in pre-mRNA splicing, but their roles in the splicing process are unknown. We show here that they associate with a postsplicing complex containing the excised intron and the spliceosomal U2, U5, and U6 snRNAs, supporting a link with a late stage in the pre-mRNA splicing process. Extract from cells that had been metabolically depleted of NO has low splicing activity and accumulates the excised intron. Also, the level of U4/U6 di-snRNP is increased but those of the free U5 and U6 snRNPs are decreased in Ntr1-depleted extract, and increased levels of U2 and decreased levels of U4 are found associated with the U5 snRNP protein Prp8. These results suggest a requirement for Ntr1 for turnover of the excised intron complex and recycling of snRNPs. Ntr1 interacts directly or indirectly with the intron release factor Prp43 and is required for its association with the excised intron. We propose that Ntr1 promotes release of excised introns from splicing complexes by acting as a spliceosome receptor or RNA-targeting factor for Prp43, possibly assisted by the Ntr2 protein.