Ruiz-Vázquez Rosa M, Nicolás Francisco E, Torres-Martínez Santiago, Garre Victoriano
Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, Murcia, Spain.
Adv Genet. 2015;91:55-102. doi: 10.1016/bs.adgen.2015.07.002. Epub 2015 Aug 7.
The basal fungus Mucor circinelloides has become, in recent years, a valuable model to study RNA-mediated gene silencing or RNA interference (RNAi). Serendipitously discovered in the late 1900s, the gene silencing in M. circinelloides is a landscape of consensus and dissents. Although similar to other classical fungal models in the basic design of the essential machinery that is responsible for silencing of gene expression, the existence of small RNA molecules of different sizes generated during this process and the presence of a mechanism that amplifies the silencing signal, give it a unique identity. In addition, M. circinelloides combines the components of RNAi machinery to carry out functions that not only limit themselves to the defense against foreign genetic material, but it uses some of these elements to regulate the expression of its own genes. Thus, different combinations of RNAi elements produce distinct classes of endogenous small RNAs (esRNAs) that regulate different physiological and developmental processes in response to environmental signals. The recent discovery of a new RNAi pathway involved in the specific degradation of endogenous mRNAs, using a novel RNase protein, adds one more element to the exciting puzzle of the gene silencing in M. circinelloides, in addition to providing hints about the evolutionary origin of the RNAi mechanism.
近年来，基础真菌卷枝毛霉已成为研究RNA介导的基因沉默或RNA干扰（RNAi）的重要模型。20世纪末偶然发现，卷枝毛霉中的基因沉默存在共识和分歧。尽管在负责基因表达沉默的基本机制的基本设计上与其他经典真菌模型相似，但在此过程中产生的不同大小的小RNA分子的存在以及放大沉默信号的机制的存在，赋予了它独特的特性。此外，卷枝毛霉结合RNAi机制的组成部分来执行功能，这些功能不仅限于对外源遗传物质的防御，还利用其中一些元件来调节自身基因的表达。因此，RNAi元件的不同组合产生了不同类别的内源性小RNA（esRNAs），它们响应环境信号调节不同的生理和发育过程。最近发现了一条新的RNAi途径，该途径利用一种新型核糖核酸酶蛋白参与内源性mRNA的特异性降解，这不仅为卷枝毛霉基因沉默这一令人兴奋的谜题增添了新元素，还为RNAi机制的进化起源提供了线索。
