Department of Biology, Texas A&M University, College Station, Texas 77843-3258.
Cold Spring Harb Perspect Biol. 2013 Oct 1;5(10):a017921. doi: 10.1101/cshperspect.a017921.
The filamentous fungus Neurospora crassa has provided a rich source of knowledge on epigenetic phenomena that would have been difficult or impossible to gain from other systems. Neurospora sports features found in higher eukaryotes but absent in both budding and fission yeast, including DNA methylation and H3K27 methylation, and also has distinct RNA interference (RNAi)-based silencing mechanisms operating in mitotic and meiotic cells. This has provided an unexpected wealth of information on gene silencing systems. One silencing mechanism, named repeat-induced point mutation (RIP), has both epigenetic and genetic aspects and provided the first example of a homology-based genome defense system. A second silencing mechanism, named quelling, is an RNAi-based mechanism that results in silencing of transgenes and their native homologs. A third, named meiotic silencing, is also RNAi-based but is distinct from quelling in its time of action, targets, and apparent purpose.
丝状真菌粗糙脉孢菌（Neurospora crassa）为表观遗传现象提供了丰富的知识来源，这些知识很难或不可能从其他系统获得。粗糙脉孢菌具有真核生物中存在但在芽殖酵母和裂殖酵母中缺失的特征，包括 DNA 甲基化和 H3K27 甲基化，并且还具有独特的 RNA 干扰（RNAi）为基础的有丝分裂和减数分裂细胞中的沉默机制。这为基因沉默系统提供了意想不到的丰富信息。一种称为重复诱导点突变（RIP）的沉默机制具有表观遗传和遗传两方面的特征，并提供了同源性基因组防御系统的第一个例子。第二种沉默机制，称为沉默现象（quelling），是一种基于 RNAi 的机制，导致转基因及其天然同源物的沉默。第三种称为减数分裂沉默（meiotic silencing），也是基于 RNAi 的，但在作用时间、靶点和明显目的上与沉默现象不同。
