INVITRO POLYADENYLATION IS STIMULATED BY THE PRESENCE OF AN UPSTREAM INTRON
INVITRO POLYADENYLATION IS STIMULATED BY THE PRESENCE OF AN UPSTREAM INTRON
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DOI：
10.1101/gad.4.9.1552
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发表时间：
1990-09-01
影响因子：
10.5
通讯作者：
BERGET, SM
中科院分区：
文献类型：
--
作者：
NIWA, M;ROSE, SD;BERGET, SM
大多数脊椎动物前体mRNA都是剪接和多腺苷酸化的。为了研究加工因子识别含有剪接和多聚腺苷酸化共有元件的最后外显子的机制，构建了含有单个内含子和多聚腺苷酸化位点的嵌合前体RNA，并测定了体外剪接和多聚腺苷酸化。嵌合RNA经历剪接和多聚腺苷酸化。这两种反应都发生在单个RNA中。内含子的存在增强了下游多聚腺苷酸位点的多聚腺苷酸化速率。刺激的程度从两到五倍不等，这取决于镁的浓度。上游内含子对多聚腺苷酸化的最大刺激需要一个3“剪接位点，但不需要一个5”剪接位点，这表明末端外显子的结构比完整上游内含子的存在更重要。我们认为，剪接和多聚腺苷酸化因子相互作用，以识别终端，聚（A）位点的外显子。这种相互作用可以解释为什么所有已知的含有内含子的真核前体mRNA通过聚腺苷酸化产生它们的3“末端。
The majority of vertebrate pre-mRNAs are both spliced and polyadenylated. To investigate the mechanism whereby processing factors recognize last exons containing both splicing and polyadenylation consensus elements, chimeric precursor RNAs containing a single intron and a poly(A) site were constructed and assayed for in vitro splicing and polyadenylation. Chimeric RNAs underwent splicing and polyadenylation. Both reactions occurred in a single RNA. The presence of an intron enhanced the rate of polyadenylation at a downstream poly(A) site. The extent of stimulation varied from two- to fivefold, depending on the magnesium concentration. Maximal stimulation of polyadenylation by an upstream intron required a 3'' splice site but not a 5'' splice site, suggesting that the structure of the terminal exon was more important than the presence of a complete upstream intron. We suggest that splicing and polyadenylation factors interact to recognize terminal, poly(A) site-containing exons. Such interaction may explain why all known intron-containing eukaryotic pre-mRNAs generate their 3'' ends by polyadenylation.