Vaucheret Hervé
Laboratoire de Biologie Cellulaire, Institut Jean-Pierre Bourgin, INRA 78026 Versailles Cedex, France.
Sci STKE. 2005 Sep 6;2005(300):pe43. doi: 10.1126/stke.3002005pe43.
Less than a year has elapsed between the discovery of trans-acting small interfering RNAs (tasiRNAs) in plants and the elucidation of the major steps of the corresponding pathway. During tasiRNA biogenesis, polyadenylated RNAs transcribed from non-protein-coding TAS genes are cleaved by a microRNA (miRNA)-programmed RNA-induced silencing complex. In contrast to classical miRNA targets, RDR6 and SGS3 convert one of the TAS RNA cleavage products into double-stranded RNA, which is subsequently processed, in a phase determined by the initial miRNA cleavage site, by DICER-LIKE 4 to generate a 21-nucleotide tasiRNA population. tasiRNAs guide endogenous mRNA cleavage through the action of AGO1 or, perhaps in some cases, AGO7. Some of the tasiRNA targets probably regulate the juvenile-to-adult phase transition, but the roles of other tasiRNA targets remain to be determined.
从植物中发现反式作用小干扰RNA（tasiRNA）到阐明相应途径的主要步骤，间隔还不到一年时间。在tasiRNA生物合成过程中，从非蛋白质编码TAS基因转录而来的多聚腺苷酸化RNA被一个由微小RNA（miRNA）编程的RNA诱导沉默复合体切割。与经典的miRNA靶标不同，RDR6和SGS3将其中一个TAS RNA切割产物转化为双链RNA，随后由DICER-LIKE 4在由初始miRNA切割位点决定的阶段进行加工，以产生一群21个核苷酸的tasiRNA。tasiRNA通过AGO1的作用，或者在某些情况下可能通过AGO7的作用，引导内源性mRNA的切割。一些tasiRNA靶标可能调控从幼年到成年的阶段转变，但其他tasiRNA靶标的作用仍有待确定。
