Intercistronic region required for polycistronic Pre-mRNA processing in Caenorhabditis elegans
Intercistronic region required for polycistronic Pre-mRNA processing in Caenorhabditis elegans
复制标题
DOI：
10.1128/mcb.21.4.1111-1120.2001
复制
发表时间：
2001-02-01
影响因子：
5.3
通讯作者：
Blumenthal, T
中科院分区：
文献类型：
--
作者：
Huang, T;Kuersten, S;Blumenthal, T
在秀丽隐杆线虫中，多顺反子前体mRNA在上游基因的3'端通过切割和多聚腺苷酸化进行加工，在下游基因的5'端通常通过反式剪接（一般剪接到特殊的剪接前导序列SL2）进行加工。先前的研究表明，在热激诱导的gpd - 2 - gpd - 3多顺反子前体mRNA的加工过程中，这两个事件之间存在关联。在此，我们通过接头扫描分析对该操纵子的顺反子间区域进行了突变分析。令人惊讶的是，3'端下游的序列对3'端形成并不重要。相反，位于3'端形成位点下游29个碱基对处的一个富含U（Ur）的元件被证明对下游mRNA的生物合成很重要。这个约20个碱基对的元件在移植到异源环境中时，足以进行SL2反式剪接和mRNA积累。此外，当下游基因被来自另一种生物的基因取代时，未观察到反式剪接特异性的丧失，这表明Ur元件可能是下游mRNA加工所需的主要信号。
In Caenorhabditis elegans, polycistronic pre-mRNAs are processed by cleavage and polyadenylation at the 3' ends of the upstream genes and trans splicing, generally to the specialized spliced leader SL2, at the 5' ends of the downstream genes. Previous studies have indicated a relationship between these two events in the processing of a heat. shock-induced gpd-2-gpd-3 polycistronic pre-mRNA, Here, we report mutational analysis of the intercistronic region of this operon by linker scan analysis, Surprisingly, no sequences downstream of the 3' end were important for 3'-end formation. In contrast, a U-rich (Ur) element located 29 bp downstream of the site of 3'-end formation was shown to be important for downstream mRNA biosynthesis. This similar to 20-bp element is sufficient for SL2 trans splicing and mRNA accumulation when transplanted to a heterologous context. Furthermore, when the downstream gene was replaced by a gene from another organism, no loss of trans-splicing specificity was observed, suggesting that the Ur element may be the primary signal required for downstream mRNA processing.