Identification of a novel sequence that governs both polyadenylation and alternative splicing in region E3 of adenovirus.
Identification of a novel sequence that governs both polyadenylation and alternative splicing in region E3 of adenovirus.
复制标题
鉴定出控制腺病毒 E3 区多聚腺苷酸化和可变剪接的新序列。
DOI：
10.1093/nar/15.22.9397
复制
发表时间：
1987
影响因子：
14.9
通讯作者：
Wold,WS
中科院分区：
文献类型：
--
作者：
Brady,HA;Wold,WS
E3区编码四种具有不同剪接模式的主要重叠mrna。有两个聚(A)位点，上游位点称为E3A，下游位点称为E3B。我们分析了在E3中缺失或插入的病毒突变体，以确定在E3前mrna的替代加工中起作用的序列，并了解是什么决定了使用哪些聚(A)位点和哪些剪接位点。在之前的研究中，我们确定了E3A多聚(A)信号的5 ‘边界位于ATTAAA序列上，现在，我们使用活的病毒突变体表明，E3A信号的3 ’边界位于ATTAAA下游47-62个核苷酸（nt）内（在最后一个微异质多聚(A)添加位点下游17-32 nt）。我们的数据进一步表明，ATTAAA，裂解位点和必要的下游序列之间的间距可能在E3A 3 '端形成中很重要。特别有趣的是，这些突变提示了一种控制替代前mrna加工的新机制。E3A 3 ‘端形成几乎完全缺陷的突变体显示，位于ATTAAA上游4nt的3 ’剪接位点的使用大大增加。使用这个3 '剪接位点的mRNA在E3B聚(A)位点被聚腺苷化。我们认为，在这种特殊情况下，替代前mrna加工可能是由参与E3A 3 '端形成或剪接的反式作用因子之间的竞争决定的。这些因子可能会竞争pre-mRNA中的重叠序列。
Region E3 encodes four major overlapping mRNAs with different splicing patterns. There are two poly(A) sites, an upstream site called E3A and a downstream site called E3B. We have analyzed virus mutants with deletions or insertions in E3 in order to identify sequences that function in the alternative processing of E3 pre-mRNAs, and to understand what determines which poly(A) sites and which splice sites are used. In previous studies we established that the 5′ boundary of the E3A poly(A) signal is at an ATTAAA sequence, We now show, using viable virus mutants, that the 3′ boundary of the E3A signal is located within 47–62 nucleotides (nt) downstream of the ATTAAA (17–32 nt downstream of the last microheterogenous poly(A) addition site). Our data further suggest that the spacing between the ATTAAA, the cleavage sites, and the essential downstream squences may be important in E3A 3′ end formation. Of particular interest, these mutants suggest a novel mechanism for the control of alternative pre-mRNA processing. Mutants which are almost completely defective in E3A 3′ end formation display greatly increased use of a 3′ splice site located 4 nt upstream of the ATTAAA. The mRNA that uses this 3′ splice site is polyadenylated at the E3B poly(A) site. We suggest, for this particular case, that alternative pre-mRNA processing could be determined by a competition betweentrans-acting factors that function in E3A 3′ end formation or in splicing. These factors could compete for overlapping sequences in pre-mRNA.