Department of Genetics and Microbiology, Faculty of Biology, University of Murcia, 30100 Murcia, Spain.
School of Natural and Exact Sciences, Pontificia Universidad Católica Madre y Maestra, 51033 Santiago de los Caballeros, Dominican Republic.
Int J Mol Sci. 2020 Dec 8;21(24):9348. doi: 10.3390/ijms21249348.
RNA interference (RNAi) was discovered at the end of last millennium, changing the way scientists understood regulation of gene expression. Within the following two decades, a variety of different RNAi mechanisms were found in eukaryotes, reflecting the evolutive diversity that RNAi entails. The essential silencing mechanism consists of an RNase III enzyme called Dicer that cleaves double-stranded RNA (dsRNA) generating small interfering RNAs (siRNAs), a hallmark of RNAi. These siRNAs are loaded into the RNA-induced silencing complex (RISC) triggering the cleavage of complementary messenger RNAs by the Argonaute protein, the main component of the complex. Consequently, the expression of target genes is silenced. This mechanism has been thoroughly studied in fungi due to their proximity to the animal phylum and the conservation of the RNAi mechanism from lower to higher eukaryotes. However, the role and even the presence of RNAi differ across the fungal kingdom, as it has evolved adapting to the particularities and needs of each species. Fungi have exploited RNAi to regulate a variety of cell activities as different as defense against exogenous and potentially harmful DNA, genome integrity, development, drug tolerance, or virulence. This pathway has offered versatility to fungi through evolution, favoring the enormous diversity this kingdom comprises.
RNA 干扰 (RNAi) 是在上个千年之交被发现的，它改变了科学家对基因表达调控的理解方式。在接下来的二十年里，人们在真核生物中发现了多种不同的 RNAi 机制，反映了 RNAi 所涉及的进化多样性。基本的沉默机制包括一种叫做 Dicer 的 RNase III 酶，它能切割双链 RNA (dsRNA) 产生小干扰 RNA (siRNA)，这是 RNAi 的一个标志。这些 siRNA 被装载到 RNA 诱导的沉默复合物 (RISC) 中，触发 Argonaute 蛋白切割互补的信使 RNA，Argonaute 蛋白是复合物的主要成分。因此，靶基因的表达被沉默。由于真菌与动物门关系密切，而且从低等真核生物到高等真核生物的 RNAi 机制都具有保守性，因此该机制在真菌中得到了深入研究。然而，RNAi 的作用，甚至其存在，在真菌界中都有所不同，因为它是为了适应每个物种的特殊性和需求而进化的。真菌利用 RNAi 来调节各种细胞活动，如防御外来和潜在有害的 DNA、基因组完整性、发育、药物耐受性或毒力。这条途径通过进化赋予了真菌多样性，促进了这个王国的巨大多样性。
