Forest Biotechnology Group, Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC 27695, USA.
Planta. 2010 Nov;232(6):1281-8. doi: 10.1007/s00425-010-1253-3. Epub 2010 Aug 20.
Artificial microRNAs (amiRNAs) are similar to microRNAs (miRNAs) in that they are able to reduce the abundance of specific transcripts in plants by RNA-Induced Silencing Complex (RISC)-mediated cleavage and degradation, but differ in that they are designed for specific targets. The long generation times of forest trees have limited the discovery of mutations by conventional genetics. AmiRNAs can create gene-specific transcript reduction in transgenic trees in a single generation and may have broad application for functional genomics of trees. In this paper, we describe the specific down-regulation of multiple genes in the phenylalanine ammonia-lyase (PAL) gene family of Populus trichocarpa using amiRNA sequences incorporated in a P. trichocarpa miRNA-producing precursor, ptc-MIR408. Two different amiRNA constructs were designed to specifically down-regulate two different subsets of PAL genes, revealing differential regulation within the gene family. Down-regulation of subset A (PAL2, PAL4 and PAL5) by amiRNA-palA led to an increase in transcript abundance of subset B (PAL1 and PAL3). The reciprocal effect was not observed.
人工 microRNAs（amiRNAs）与 microRNAs（miRNAs）相似，它们能够通过 RNA 诱导沉默复合物（RISC）介导的切割和降解来降低植物中特定转录本的丰度，但它们的不同之处在于它们是针对特定靶标设计的。林木的长世代时间限制了传统遗传学中突变的发现。amiRNA 可以在单个世代中在转基因树木中产生基因特异性转录本的减少，并且可能在树木的功能基因组学中有广泛的应用。在本文中，我们描述了使用整合在杨树 miR408 产生前体中的 amiRNA 序列，特异性下调杨树苯丙氨酸解氨酶（PAL）基因家族中的多个基因。设计了两种不同的 amiRNA 构建体，以特异性下调 PAL 基因的两个不同亚群，揭示了基因家族内的差异调控。amiRNA-palA 对亚群 A（PAL2、PAL4 和 PAL5）的下调导致亚群 B（PAL1 和 PAL3）的转录本丰度增加。没有观察到相反的效果。
