Shen Binzhang, Goodman Howard M
Department of Genetics, Harvard Medical School, and Department of Molecular Biology, Massachusetts General Hospital, 50 Blossom Street, Boston, MA 02114, USA.
Science. 2004 Nov 5;306(5698):997. doi: 10.1126/science.1103521.
One of the important roles of microRNA (miRNA) is to direct the cleavage of messenger RNA (mRNA). However, the mechanisms of decay of the cleaved mRNA products is not well understood. We show that miRNA-directed cleavage products in organisms as diverse as Arabidopsis, mouse, and Epstein-Barr virus have at their 3' ends a stretch (1 to 24 nucleotides) of oligouridine posttranscriptionally added downstream of the cleavage site. This 3' uridine addition, as shown for Arabidopsis, is correlated with decapping and 5' shortening of the cleaved products, suggesting a mechanistic step in the miRNA-directed mRNA decay mechanism.
微小RNA（miRNA）的重要作用之一是指导信使核糖核酸（mRNA）的切割。然而，切割后的mRNA产物的降解机制尚未完全明确。我们发现，在拟南芥、小鼠和爱泼斯坦-巴尔病毒等多种生物中，miRNA指导的切割产物在其3'端有一段（1至24个核苷酸）寡聚尿苷酸，这是在切割位点下游转录后添加的。如拟南芥所示，这种3'端尿苷酸添加与切割产物的脱帽和5'端缩短相关，这表明它是miRNA指导的mRNA降解机制中的一个机制步骤。
