Trans-splicing and polyadenylation of let-7 microRNA primary transcripts
Trans-splicing and polyadenylation of let-7 microRNA primary transcripts
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DOI：
10.1261/rna.7122604
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发表时间：
2004-10-01
期刊：
影响因子：
4.5
通讯作者：
Pasquinelli, AE
中科院分区：
文献类型：
--
作者：
Bracht, J;Hunter, S;Pasquinelli, AE
microRNA（miRNA）类22个核苷酸的RNAs的成员调节含有反义互补序列的靶基因的表达。miRNA的成熟涉及较长的初级转录物的切割，但关于miRNA基因如何转录并进入加工途径还知之甚少。我们发现，相对较长的，多腺苷酸化的成绩单编码的秀丽隐杆线虫let-7基因进行反式剪接的剪接前导1（SL 1）RNA。成熟let-7序列上游的缺失，包括反式剪接位点的去除，导致初级转录物的稳定积累和成熟let-7 RNA在体内的受损产生。我们的数据表明let-7 miRNA生物发生的多个步骤可以解偶联，从而允许在功能性miRNA的产生中进行复杂的调节。最后，let-7初级转录物经历剪接的观察结果突出了鉴定被细胞加工机制识别的内源性pri-miRNA底物序列的重要性。
Members of the microRNA (miRNA) class of 22-nucleotide RNAs regulate the expression of target genes that contain sequences of antisense complementarity. Maturation of miRNAs involves cleavage of longer primary transcripts, but little is yet understood about how miRNA genes are transcribed and enter the processing pathway. We find that relatively long, polyadenylated transcripts encoded by the Caenorhabditis elegans let-7 gene undergo trans-splicing to the spliced leader 1 (SL1) RNA. Deletions, including removal of the trans-splice site, upstream of mature let-7 sequence result in stable accumulation of primary transcripts and compromised production of mature let-7 RNA in vivo. Our data show that multiple steps of let-7 miRNA biogenesis can be uncoupled, allowing for complex regulation in the production of a functional miRNA. Finally, the observation that let-7 primary transcripts undergo splicing highlights the importance of identifying the sequence of endogenous pri-miRNA substrates recognized by the cellular processing machinery.