Activation of a cryptic 5′ splice site by U1 snRNA
Activation of a cryptic 5′ splice site by U1 snRNA
复制标题
DOI：
10.1017/s1355838201002448
复制
发表时间：
2001-03-01
期刊：
影响因子：
4.5
通讯作者：
Wise, JA
中科院分区：
文献类型：
--
作者：
Alvarez, CJ;Wise, JA
在分析粟酒裂殖酵母cdc2第二内含子中5 '剪接位点突变的过程中，我们鉴定了在+2位含有非共有核苷酸的隐蔽5 '连接。这个神秘的5 '连接的一个更不寻常的特征是它的激活模式。通过分析一系列cdc2突变体在存在和不存在补偿性U1等位基因的情况下的剪接产物谱，我们获得了天然5 '剪接位点参与隐蔽5 '剪接位点激活的证据，并且它通过与U1 snRNA的碱基配对来实现。后续实验的结果有力地表明，U1 snRNA和隐蔽5 ′连接本身之间的碱基配对在其激活中起主导作用。最值得注意的是，突变体U1甚至在天然5 '连接处存在野生型序列的情况下也可以激活隐蔽的5 '剪接位点，这提供了明确的证据，即该snRNA通过碱基配对重定向剪接。尽管先前的工作已经证明U5和U6 snRNA可以通过碱基配对相互作用激活隐蔽的5 '剪接位点，这是U1snRNA与隐蔽5 ′连接的最终选择有关的第一个例子。
In the course of analyzing 5 ' splice site mutations in the second intron of Schizosaccharomyces pombe cdc2, we identified a cryptic 5 ' junction containing a nonconsensus nucleotide at position +2. An even more unusual feature of this cryptic 5 ' junction was its pattern of activation. By analyzing the profile of splicing products for an extensive series of cdc2 mutants in the presence and absence of compensatory U1 alleles, we have obtained evidence that the natural 5 ' splice site participates in activation of the cryptic 5 ' splice site, and that it does so via base pairing to U1 snRNA, Furthermore, the results of follow-up experiments strongly suggest that base pairing between U1 snRNA and the cryptic 5 ' junction itself plays a dominant role in its activation. Most remarkably, a mutant U1 can activate the cryptic 5 ' splice site even in the presence of a wild-type sequence at the natural 5 ' junction, providing unambiguous evidence that this snRNA redirects splicing via base pairing, Although previous work has demonstrated that U5 and U6 snRNAs can activate cryptic 5 ' splice sites through base pairing interactions, this is the first example in which U1 snRNA has been implicated in the final selection of a cryptic 5 ' junction.