Untemplated oligoadenylation promotes degradation of RISC-cleaved transcripts
Untemplated oligoadenylation promotes degradation of RISC-cleaved transcripts
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DOI：
10.1126/science.1135268
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发表时间：
2006-12-22
期刊：
影响因子：
56.9
通讯作者：
Cerutti, Heriberto
中科院分区：
文献类型：
--
作者：
Ibrahim, Fadia;Rohr, Jennifer;Cerutti, Heriberto
双链RNA在真核生物中通过多种途径触发基因沉默，被DICER加工成小干扰RNA(SiRNAs)并被整合到RNA诱导沉默复合体(RISC)中。RNA干扰涉及同源转录物的降解，是最具特征性的机制。然而，由siRNA指导的切割导致的RNA片段的命运尚不清楚。我们已经在单细胞绿藻衣藻中发现了一个基因(MUT68)，它是siRNA靶向转录有效衰减所必需的。MUT68编码一个非规范的多聚腺苷聚合酶，它在siRNA介导的切割后将未模板腺嘌呤添加到5‘RNA片段中，似乎刺激了它们的外切体依赖的降解。
Double-stranded RNA, processed to small interfering RNAs (siRNAs) by Dicer and incorporated into the RNA-induced silencing complex (RISC), triggers gene silencing by a variety of pathways in eukaryotes. RNA interference involving the degradation of homologous transcripts is the best-characterized mechanism. However, the fate of the RNA fragments resulting from siRNA-directed cleavage is poorly understood. We have identified a gene (MUT68) in the unicellular green algaChlamydomonas reinhardtiithat is required for the efficient decay of siRNA-targeted transcripts.MUT68encodes a noncanonical polyadenylate polymerase that adds untemplated adenines to the 5′ RNA fragments after siRNA-mediated cleavage and appears to stimulate their exosome-dependent degradation.