Identification of cis elements directing termination of yeast nonpolyadenylated snoRNA transcripts
Identification of cis elements directing termination of yeast nonpolyadenylated snoRNA transcripts
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DOI：
10.1128/mcb.24.14.6241-6252.2004
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发表时间：
2004-07-01
影响因子：
5.3
通讯作者：
Corden, JL
中科院分区：
文献类型：
--
作者：
Carroll, KL;Pradhan, DA;Corden, JL
RNA聚合酶II（Pol II）终止由新生转录物中存在的序列触发。前体mRNA转录的终止与指导前体mRNA的切割和聚腺苷酸化的顺式作用序列的识别相关联。终止非聚腺苷酸化[non-poly（A）] Pol II在酿酒酵母中的转录需要RNA结合蛋白Nrd 1和Nab 3。我们已经使用突变策略来表征SNR 13和SNR 47 snoRNA基因下游的非poly（A）终止元件。这种方法检测到两种常见的RNA序列基序，GUA[AG]和UCUU。第一个基序对应于已知的Nrd 1结合位点，我们已经验证了凝胶迁移率变动分析。我们还表明，Nab 3蛋白特异性结合到RNA含有UCUU基序。总之，我们的数据表明，Nrd 1和Nab 3结合位点在定义非poly（A）终止子中起着重要作用。与poly（A）终止子的情况一样，对于非poly（A）终止子没有强烈的共识，并且Nrd 1 p和Nab 3 p结合位点的排列变化很大。此外，这些序列的组织即使在密切相关的酵母中也不是高度保守的。这表明存在很大程度的遗传变异性。尽管存在这种变异性，但我们能够使用计算模型表明Nrd 1和Nab 3的结合位点可以识别转录终止由这些蛋白质介导的基因。
RNA polymerase II (Pol II) termination is triggered by sequences present in the nascent transcript. Termination of pre-mRNA transcription is coupled to recognition of cis-acting sequences that direct cleavage and polyadenylation of the pre-mRNA. Termination of nonpolyadenylated [non-poly(A)] Pol II transcripts in Saccharomyces cerevisiae requires the RNA-binding proteins Nrd1 and Nab3. We have used a mutational strategy to characterize non-poly(A) termination elements downstream of the SNR13 and SNR47 snoRNA genes. This approach detected two common RNA sequence motifs, GUA[AG] and UCUU. The first motif corresponds to the known Nrd1-binding site, which we have verified here by gel mobility shift assays. We also show that Nab3 protein binds specifically to RNA containing the UCUU motif. Taken together, our data suggest that Nrd1 and Nab3 binding sites play a significant role in defining non-poly(A) terminators. As is the case with poly(A) terminators, there is no strong consensus for non-poly(A) terminators, and the arrangement of Nrd1p and Nab3p binding sites varies considerably. In addition, the organization of these sequences is not strongly conserved among even closely related yeasts. This indicates a large degree of genetic variability. Despite this variability, we were able to use a computational model to show that the binding sites for Nrd1 and Nab3 can identify genes for which transcription termination is mediated by these proteins.