POINT MUTATIONS IN AAUAAA AND THE POLY(A) ADDITION SITE - EFFECTS ON THE ACCURACY AND EFFICIENCY OF CLEAVAGE AND POLYADENYLATION INVITRO
POINT MUTATIONS IN AAUAAA AND THE POLY(A) ADDITION SITE - EFFECTS ON THE ACCURACY AND EFFICIENCY OF CLEAVAGE AND POLYADENYLATION INVITRO
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DOI：
10.1093/nar/18.19.5799
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发表时间：
1990-10-11
影响因子：
14.9
通讯作者：
WICKENS, MP
中科院分区：
文献类型：
--
作者：
SHEETS, MD;OGG, SC;WICKENS, MP
在脊椎动物mrna中，聚(A)添加位点附近的三个序列是保守的。我们在体外分析了AAUAAA每个位置的单碱基变化的影响，以及在3'端形成中加入poly (A)的核苷酸。AAUAAA序列的所有18个可能的单碱基变化都大大减少了poly (A)在poly (A)添加位点末端的rna上的添加，并阻止了延伸到poly (A)添加位点以外的rna的切割。随着位置的改变和碱的引入，减小的幅度变化很大。对于任何给定的突变，切割和聚腺苷酸化都减少到相似的程度，这强烈表明在这两种反应中相同的因子与AAUAAA相互作用。在加了poly (A)的保守腺苷及其附近的突变会干扰3”末端形成的准确性，而不是效率。例如，保守腺苷的点突变将最丰富的5”半分子的3”端向下游移动一个核苷酸。讨论了这些突变对3‘’末端形成精度的影响机制。
Three sequences in the vicinity of poly (A) addition sites are conserved among vertebrate mRNAs. We analyze the effects of single base changes in each position of AAUAAA and in the nucleotide to which poly (A) is added on 3'' end formation in vitro. All 18 possible single base changes of the AAUAAA sequence greatly reduce addition of poly (A) to RNAs that end at the poly (A) addition site, and prevent cleavage of RNAs that extend beyond. The magnitude of reduction varies greatly with the position changed and the base introduced. For any given mutation, cleavage and polyadenylation are reduced to similar extents, strongly suggesting that the same factor interacts with AAUAAA in both reactions. Mutations at and near the conserved adenosine to which poly (A) is added disturb the accuracy, but not the efficiency, of 3'' end formation. For example, point mutations at the conserved adenosine shift the 3'' end of the most abundant 5'' half-molecule downstream by a single nucleotide. The mechanism by which these mutations might exert their effects on the precision of 3'' end formation are discussed.