The nuclear dsRNA binding protein HYL1 is required for MicroRNA accumulation and plant development, but not posttranscriptional transgene silencing
The nuclear dsRNA binding protein HYL1 is required for MicroRNA accumulation and plant development, but not posttranscriptional transgene silencing
复制标题
DOI：
10.1016/j.cub.2004.01.035
复制
发表时间：
2004-02-17
期刊：
影响因子：
9.2
通讯作者：
Vaucheret, H
中科院分区：
文献类型：
--
作者：
Vazquez, F;Gasciolli, V;Vaucheret, H
MicroRNA (miRNA) 是由不完美的双链 RNA (dsRNA) 加工而成的 21-24 个核苷酸长的分子。它们通过靶向互补 mRNA 进行切割或干扰其翻译来调节基因表达 [1-6]。在拟南芥中，核 DICER-LIKE1 (DCL1) 或 HEN1 蛋白的点突变或短截断会减少 miRNA 积累并增加未切割的靶标 mRNA 积累，从而导致发育异常 [7-12]。在这里，我们表明 miRNA 积累还取决于 HYL1（一种核 dsRNA 结合蛋白）的活性 [13]。 hyl1 突变体表现出与 dcl1 和 hen1 突变体重叠的发育缺陷，表明 DCL1、HEN1 和 HYL1 在细胞核中共同作用。我们验证了其他靶标 mRNA，并表明 hyl1 中 miRNA 积累的减少与未切割靶标 mRNA（包括分生组织和生长素相关基因）积累的增加相关，这为 hyl1 的发育异常以及之前将 hyl1 鉴定为对植物激素反应改变的突变体提供了线索 [13]。最后，我们发现 hyl1 中发生转录后转基因沉默，表明 HYL1 在植物 miRNA 通路中具有特殊功能，而 HYL1 相关的 RDE-4 和 R2D2 蛋白与细胞质中的 DICER 相关，并分别在秀丽隐杆线虫和果蝇的 RNAi 通路中发挥作用 [14-15]。
MicroRNAs (miRNAs) are 21-24 nucleotides long molecules processed from imperfect double-stranded RNAs (dsRNAs). They regulate gene expression by targeting complementary mRNA for cleavage or interfering with their translation [1-6]. In Arabidopsis, point mutations in or short truncations of the nuclear DICER-LIKE1 (DCL1) or HEN1 protein reduce miRNA accumulation and increase uncleaved target mRNAs accumulation, resulting in developmental abnormalities [7-12]. Here, we show that miRNA accumulation also depends on the activity of HYL1, a nuclear dsRNA binding protein [13]. hyl1 mutants exhibit developmental defects overlapping with that of dcl1 and hen1 mutants, suggesting that DCL1, HEN1, and HYL1 act together in the nucleus. We validate additional target mRNAs and show that reduced miRNA accumulation in hyl1 correlates with an increased accumulation of uncleaved target mRNAs, including meristem- and auxin-related genes, providing clues for the developmental abnormalities of hyl1 and for the previous identification of hyl1 as a mutant with altered responses to phytohormones [13]. Lastly, we show that posttranscriptional transgene silencing occurs in hyl1, suggesting that HYL1 has specialized function in the plant miRNA pathway, whereas the HYL1-related RDE-4 and R2D2 proteins associate with DICER in the cytoplasm and act in the RNAi pathway in C. elegans and Drosophila, respectively [14-15].