AtXRN4 degrades mRNA in Arabidopsis and its substrates include selected miRNA targets
AtXRN4 degrades mRNA in Arabidopsis and its substrates include selected miRNA targets
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DOI：
10.1016/j.molcel.2004.06.006
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发表时间：
2004-07-23
期刊：
影响因子：
16
通讯作者：
Green, PJ
中科院分区：
文献类型：
--
作者：
Souret, FF;Kastenmayer, JP;Green, PJ
信使 RNA 降解是基因表达中的一个重要步骤，可以通过 siRNA 或 miRNA 进行调节。然而，我们对体内真核生物 mRNA 降解机制的大部分了解都来自酿酒酵母，它缺乏 miRNA 和 RNAi 能力。通过反向遗传和微阵列分析，我们鉴定了 AtXRN4 的多种底物，AtXRN4 是主要酵母 mRNA 降解核糖核酸外切酶 Xrn1p 的拟南芥同源物。 AtXRN4 的插入突变导致多个 mRNA 3' 端的积累，其方式与 3' 端的稳定性增加相关，并且在与 AtXRN4 互补后发生逆转。此外，miRNA 介导的 SCARECROW-LIKE 转录物和其他几种 miRNA 靶转录物裂解的 3' 产物也在 xrn4 突变体中积累。 Xrn1p 同源物可降解多细胞真核生物中的 mRNA，并有助于 miRNA 介导的选定靶标的衰变途径，这对其他生物体中的 XRN 具有重要意义。
Messenger RNA degradation is an essential step in gene expression that can be regulated by siRNAs or miRNAs. However, most of our knowledge of in vivo eukaryotic mRNA degradation mechanisms derives from Saccharomyces cerevisiae, which lacks miRNAs and RNAi capability. Using reverse genetic and microarray analyses, we have identified multiple substrates of AtXRN4, the Arabidopsis homolog of the major yeast mRNA degrading exoribonuclease, Xrn1p. Insertional mutation of AtXRN4 leads to accumulation of the 3' end of several mRNAs, in a manner that correlates with increased stability of the 3' end, and is reversed following complementation with AtXRN4. Moreover, 3' products of miRNA-mediated cleavage of SCARECROW-LIKE transcripts and several other miRNA target transcripts are among those that accumulate in xrn4 mutants. The demonstration that an Xrn1p homolog degrades mRNA in a multicellular eukaryote and contributes to the miRNA-mediated decay pathway of selected targets has implications for XRNs in other organisms.