Identification of nuclear dicing bodies containing proteins for microRNA biogenesis in living Arabidopsis plants
Identification of nuclear dicing bodies containing proteins for microRNA biogenesis in living Arabidopsis plants
复制标题
DOI：
10.1016/j.cub.2007.04.005
复制
发表时间：
2007-05-01
期刊：
影响因子：
9.2
通讯作者：
Spector, David L.
中科院分区：
文献类型：
--
作者：
Fang, Yuda;Spector, David L.
microRNAs（miRNAs）是多细胞生物中重要的基因表达调控分子。miRNA加工是一个两步过程。在动物细胞中，第一步是细胞核，第二步是细胞质，而在植物细胞中，这两个步骤都通过酶Dicer样1（DCL 1）[1，2]和其他蛋白质（包括锌指结构域蛋白锯齿（SE）[3，4]和双链RNA（dsRNA）结合结构域蛋白Hyponastic Leukemia 1（HYL 1）[5-7]）在细胞核中发生。此外，植物miRNA在其3'端被Hua增强子（HEN 1）甲基化[8]并加载到Argonaute 1（AGO 1）上[9]。然而，关于miRNA生物发生的细胞基础知之甚少。使用活细胞成像，我们在这里显示，DCL 1和HYL 1共定位在离散的核体除了存在于一个低水平的弥漫性核质分布。这些体，我们称之为核切割体（D-体），不同于卡哈尔体[10，11]。在miRNA加工中功能受损的突变的DCL 1福尔斯靶向D体，并且引入的初级（pri）-miRNA转录物被募集到D体。此外，双分子荧光互补（BiFC）表明，DCL 1，HYL 1和SE在D-体中相互作用。在这些数据的基础上，我们提出，D-体是至关重要的协调pri-miRNA加工和/或存储/组装的miRNA加工复合物在植物细胞核中。
MicroRNAs (miRNAs) are important for regulating gene expression in muticellular organisms. MiRNA processing is a two-step process. In animal cells, the first step is nuclear and the second step cytoplasmic, whereas in plant cells, both steps occur in the nucleus via the enzyme Dicer-like1 (DCL1) [1, 2] and other proteins including the zinc-finger-domain protein Serrate (SE) [3, 4] and a double-stranded RNA (dsRNA) binding-domain protein, Hyponastic Leaves1 (HYL1) [5-7]. Furthermore, plant miRNAs are methylated by Hua Enhancer (HEN1) at their 3' ends [8] and loaded onto Argonaute1 (AGO1) [9]. However, little is known about the cellular basis of miRNA biogenesis. Using live-cell imaging, we show here that DCL1 and HYL1 colocalize in discrete nuclear bodies in addition to being present in a low-level diffuse nucleoplasmic distribution. These bodies, which we refer to as nuclear dicing bodies (D-bodies), differ from Cajal bodies [10, 11]. A mutated DCL1 with impaired function in miRNA processing falls to target to D-bodies, and an introduced primary (pri)-miRNA transcript is recruited to D-bodies. Furthermore, bimolecular fluorescence complementation (BiFC) shows that DCL1, HYL1, and SE interact in D-bodies. On the basis of these data, we propose that D-bodies are crucial for orchestrating pri-miRNA processing and/or storage/assembly of miRNA-processing complexes in the nuclei of plant cells.