Pre-mRNA processing factors are required for nuclear export
Pre-mRNA processing factors are required for nuclear export
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DOI：
10.1017/s1355838200001059
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发表时间：
2000-12-01
期刊：
影响因子：
4.5
通讯作者：
Silver, PA
中科院分区：
文献类型：
--
作者：
Brodsky, AS;Silver, PA
RNA从细胞核的输出被认为与适当的加工和包装成核糖核蛋白蛋白复合物有关。通过将U1A RNA结合蛋白与绿色荧光蛋白融合，以跟踪具有U1A发夹结构的特定mRNA，开发了观察活酵母细胞中mRNA核输出的系统。检测了编码Rp125、Pgk1和Ssa4的RNA的3'UTR、内含子、RNA加工因子、核孔蛋白和转运因子对其输出的影响。所有这些都聚集在细胞核中，影响核输出机制和某些核孔蛋白的成分。然而，在应激条件下，PGK1和RPL 25转录物在细胞核中积累，而SSA4 RNA被输出。此外，当输出被阻断时，只有含有ASH13'UTR的RNA在核仁中积累。剪接机制中的突变选择性地阻断了仅含内含子的RNA的输出。RNA 14、RNA 15和PAP 1中的突变，其编码对3'加工重要的因子，也阻断了所有RNA的输出，包括SSA 4，从而将输出与多腺苷酸化过程联系起来。总之，这些数据以图形方式显示了mRNA加工和核输出之间的联系。
RNA export from the nucleus is thought to be linked to proper processing and packaging into ribonucleoprotein protein complexes. A system to observe mRNA nuclear export in living yeast cells was developed by fusing the U1A RNA-binding protein to the green fluorescent protein to follow specific mRNAs with U1A hairpins engineered into them. RNAs encoding Rp125, Pgkl, and Ssa4 were examined for the effects of 3' UTRs, introns, RNA processing factors, nucleoporins, and transport factors on their export. All accumulated in the nucleus in mutants affecting components of the nuclear export machinery and certain nucleoporins. However, under conditions of stress, PGK1 and RPL25 transcripts accumulate in the nucleus whereas SSA4 RNA is exported. Moreover, when export is blocked, only RNAs containing the ASH13'UTR accumulated in the nucleolus. Mutations in the splicing machinery selectively blocked export of only intron-containing RNAs. Mutations in RNA14 RNA15, and PAP1, which encode factors important for 3' processing, also blocked export of all RNAs, including SSA4 thereby linking export to the process of polyadenlyation. Taken together, these data graphically display the connections between mRNA processing and nuclear export.