ARE U4 SMALL NUCLEAR RIBONUCLEOPROTEINS INVOLVED IN POLYADENYLATION
ARE U4 SMALL NUCLEAR RIBONUCLEOPROTEINS INVOLVED IN POLYADENYLATION
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DOI：
10.1038/309179a0
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发表时间：
1984-01-01
期刊：
影响因子：
64.8
通讯作者：
BERGET, SM
中科院分区：
文献类型：
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作者：
BERGET, SM
真核前信使 RNA 多腺苷酸化的机制尚不清楚。大多数聚腺苷酸化模型都会在 Poly(A) 添加位点对前体转录本进行切割，然后通过 Poly(A) 聚合酶 1-5 聚合 A 残基。对聚 (A) 添加位点周围的序列的分析已确定共有识别序列元件 AAUAAA 对于聚腺苷酸化来说是必需的，但还不够6-14。 Benoitet al.15 观察到第二个识别序列元件 CACUG 与几个测序 RNA 中的 Poly(A) 添加位点相邻。在这里，我们分析了 61 个脊椎动物的 Poly(A) 添加序列，定义了比之前识别的更广泛的多聚腺苷酸化识别序列，并提出了如何选择 Poly(A) 添加位点的建议。此外，我们发现定义的识别序列具有与小核RNA U4内的区域互补的元件，这表明U4小核核糖核蛋白（snRNP）可能以类似于U1 snRNP在剪接中的作用的方式介导多腺苷酸化。该模型调用 U4 RNA 与 AAUAAA 识别元件的杂交（与初级位点选择相关），以及与 CAYUG 识别元件的杂交（与切割位点选择相关）。
The mechanism whereby eukaryotic pre-messenger RNAs are polyadenylated is unknown. Most models for polyadenylation invoke cleavage of precursor transcripts at the site of poly(A) addition followed by polymerization of A residues by poly( A) polymerase1–5. Analysis of the sequences surrounding poly(A) addition sites has identified the consensus recognition sequence element AAUAAA as necessary but not sufficient for polyadenylation6–14. A second recognition sequence element CACUG, was observed by Benoitet al.15to be adjacent to the site of poly(A) addition in several sequenced RNAs. Here, we analyse 61 vertebrate poly(A) addition sequences, define a more extensive recognition sequence for polyadenylation than previously recognized and suggest how the site of poly(A) addition may be chosen. Furthermore, we find that the defined recognition sequence has elements which are complementary to regions within the small nuclear RNA U4, suggesting that U4 small nuclear ribonucleoproteins (snRNPs) may mediate polyadenylation in a fashion similar to the role of U1 snRNPs in splicing. The model invokes hybridization of U4 RNA to AAUAAA recognition elements as related to primary site selection, and hybridization to CAYUG recognition elements as related to cleavage site selection.