Nucleocytoplasmic transport and processing of small nuclear RNA precursors.
Nucleocytoplasmic transport and processing of small nuclear RNA precursors.
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小核 RNA 前体的核质运输和加工。
DOI：
10.1128/mcb.10.7.3365-3375.1990
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发表时间：
1990
影响因子：
5.3
通讯作者：
Dahlberg,JE
中科院分区：
文献类型：
--
作者：
NeumandeVegvar,HE;Dahlberg,JE
我们分析了小核RNA （snRNA）前体在其合成和成熟的不同阶段的结构和位置。在脉冲标记的非洲爪蟾卵细胞细胞核中，我们检测到snrna在其3'端比成熟形式长多达10个核苷酸。对这些rna的5'帽分析和脉冲追踪实验表明，这些核snrna是过去观察到的细胞质前snrna的前体。小麦胚芽凝集素并没有阻止前snrna的合成，这抑制了前snrna从细胞核的输出，这表明这些rna的合成并没有强制耦合到它们的输出。新合成的U1 rna可以从细胞核中输出，而与3‘端长度无关，但在其3’端延长约10个核苷酸以上的pre-U1 rna是细胞质中较差的修剪底物。3'端的结构对RNA随后转运回细胞核至关重要。这一要求确保截断和未完全加工的Ul rna被排除在细胞核之外。
We have analyzed the structures and locations of small nuclear RNA (snRNA) precursors at various stages in their synthesis and maturation. In the nuclei of pulse-labeledXenopus laevisoocytes, we detected snRNAs that were longer than their mature forms at their 3' ends by up to 10 nucleotides. Analysis of the 5' caps of these RNAs and pulse-chase experiments showed that these nuclear snRNAs were precursors of the cytoplasmic pre-snRNAs that have been observed in the past. Synthesis of pre-snRNAs was not abolished by wheat germ agglutinin, which inhibits export of the pre-snRNAs from the nucleus, indicating that synthesis of these RNAs is not obligatorily coupled to their export. Newly synthesized U1 RNAs could be exported from the nucleus regardless of the length of the 3' extension, but pre-U1 RNAs that were elongated at their 3' ends by more than about 10 nucleotides were poor substrates for trimming in the cytoplasm. The structure at the 3' end was critical for subsequent transport of the RNA back to the nucleus. This requirement ensures that truncated and incompletely processed Ul RNAs are excluded from the nucleus.