Pre-spliceosome formation in S.pombe requires a stable complex of SF1-U2AF59-U2AF23
Pre-spliceosome formation in S.pombe requires a stable complex of SF1-U2AF59-U2AF23
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DOI：
10.1093/emboj/cdf555
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发表时间：
2002-10-15
期刊：
影响因子：
11.4
通讯作者：
Query, CC
中科院分区：
文献类型：
--
作者：
Huang, T;Vilardell, J;Query, CC
我们已经开始了从裂殖酵母裂殖酵母提取物中的剪接复合物的生化分析。粟酒裂殖酵母的提取物含有高水平的剪接体样U2/5/6三-snRNP，其在ATP存在下解离成单-snRNP，并支持U2 snRNP与内含子的3'端结合，产生弱的ATP非依赖性E复合物和稳定的ATP依赖性复合物A。粟酒裂殖酵母复合物A形成的要求（前mRNA序列元件、蛋白质剪接因子、SF 1/BBP和U2 AF的两个亚基）类似于哺乳动物复合物A的要求。粟酒裂殖酵母SF 1/BBP、U2 AF（59）和U2 AF（23）在复合物A形成所需的新复合物中紧密缔合。这种预先形成的SF 1-U2 AF（59）-U2 AF（23）复合物可能代表了识别内含子3'端的分支位点、嘧啶区和3'剪接位点的流线型机制。
We have initiated a biochemical analysis of splicing complexes in extracts from the fission yeast Schizosaccharomyces pombe. Extracts of S.pombe contain high levels of the spliceosome-like U2/5/6 tri-snRNP, which dissociates into mono-snRNPs in the presence of ATP, and supports binding of U2 snRNP to the 3' end of introns, yielding a weak ATP-independent E complex and the stable ATP-dependent complex A. The requirements for S.pombe complex A formation (pre-mRNA sequence elements, protein splicing factors, SF1/BBP and both subunits of U2AF) are analogous to those of mammalian complex A. The S.pombe SF1/BBP, U2AF(59) and U2AF(23) are tightly associated in a novel complex that is required for complex A formation. This pre-formed SF1-U2AF(59)-U2AF(23) complex may represent a streamlined mechanism for recognition of the branch site, pyrimidine tract and 3' splice site at the 3' end of introns.