Gene silencing in Neurospora crassa requires a protein homologous to RNA-dependent RNA polymerase
Gene silencing in Neurospora crassa requires a protein homologous to RNA-dependent RNA polymerase
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DOI：
10.1038/20215
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发表时间：
1999-05-13
期刊：
影响因子：
64.8
通讯作者：
Macino, G
中科院分区：
文献类型：
--
作者：
Cogoni, C;Macino, G
在植物和真菌中，转基因的引入可导致转录后基因沉默（1,2）。在这种现象中，转基因以及含有与转基因同源序列的内源基因的表达可能会被阻断，它与病毒抗性（3 - 5）和基因组维持（6,7）有关。转基因诱导的基因沉默在粗糙脉孢菌中被称为基因压制，在植物中被称为共抑制。已经分离出了粗糙脉孢菌中基因压制缺陷（qde）突变体，在这些突变体中，转基因诱导的基因沉默受到损害（8）。在此我们报道qde - 1的克隆，它是被分离出的基因沉默机制的第一个细胞组分，它定义了一个在包括植物、动物和真菌在内的不同物种中保守的新基因家族。qde - 1基因产物类似于在番茄中发现的一种依赖RNA的RNA聚合酶（9）。qde - 1的鉴定有力地支持了在转录后基因沉默机制中涉及一种依赖RNA的RNA聚合酶的模型。qde - 1同源物在多种植物和真菌物种中的存在表明可能存在一种保守的基因沉默机制，它可能是为了保持基因组完整性以及保护基因组免受天然存在的转座子和病毒的侵害而进化出来的。
In plants and fungi, the introduction of transgenes can lead to post-transcriptional gene silencing(1,2). This phenomenon, in which expression of the transgene and of endogenous genes containing sequences homologous to the transgene can be blocked, is involved in virus resistance(3-5) and genome maintenance(6,7). Transgene-induced gene silencing has been termed quelling in Neurospora crassa and co-suppression in plants. Quelling-defective (qde) mutants of N. crassa, in which transgene-induced gene silencing is impaired, have been isolated(8). Here we report the cloning of qde-1, the first cellular component of the gene-silencing mechanism to be isolated, which defines a new gene family conserved among different species including plants, animals and fungi. The qde-1 gene product is similar to an RNA-dependent RNA polymerase found in the tomato(9). The identification of qde-1 strongly supports models that implicate an RNA-dependent RNA polymerase in the post-transcriptional gene-silencing mechanism. The presence of qde-1 homologues in a variety of species of plants and fungi indicates that a conserved gene-silencing mechanism may exist, which could have evolved to preserve genome integrity and to protect the genome against naturally occurring transposons and viruses.