Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, Faculty of Science, The Hebrew University of Jerusalem, 9190401, Jerusalem, Israel.
The Marine Biological Association of the United Kingdom, Citadel Hill, Plymouth, UK.
Nat Commun. 2020 Dec 3;11(1):6187. doi: 10.1038/s41467-020-20003-8.
MicroRNAs (miRNAs) base-pair to messenger RNA targets and guide Argonaute proteins to mediate their silencing. This target regulation is considered crucial for animal physiology and development. However, this notion is based exclusively on studies in bilaterians, which comprise almost all lab model animals. To fill this phylogenetic gap, we characterize the functions of two Argonaute paralogs in the sea anemone Nematostella vectensis of the phylum Cnidaria, which is separated from bilaterians by ~600 million years. Using genetic manipulations, Argonaute-immunoprecipitations and high-throughput sequencing, we provide experimental evidence for the developmental importance of miRNAs in a non-bilaterian animal. Additionally, we uncover unexpected differential distribution of distinct miRNAs between the two Argonautes and the ability of one of them to load additional types of small RNAs. This enables us to postulate a novel model for evolution of miRNA precursors in sea anemones and their relatives, revealing alternative trajectories for metazoan miRNA evolution.
微小 RNA（miRNAs）与信使 RNA 靶标碱基配对，并引导 Argonaute 蛋白介导其沉默。这种靶标调控被认为对动物生理学和发育至关重要。然而，这种观点仅基于对包括几乎所有实验室模型动物在内的两侧对称动物的研究。为了填补这一系统发育空白，我们对腔肠动物门海葵 Nematostella vectensis 的两个 Argonaute 同源基因的功能进行了描述，腔肠动物与两侧对称动物的分化时间约为 6 亿年。通过遗传操作、Argonaute 免疫沉淀和高通量测序，我们为非两侧对称动物中 miRNAs 在发育中的重要性提供了实验证据。此外，我们还揭示了不同 miRNAs 在两个 Argonautes 之间的分布存在差异，以及其中一个 Argonaute 加载其他类型小 RNA 的能力。这使我们能够提出一个关于海葵及其亲属 miRNA 前体进化的新模型，揭示了后生动物 miRNA 进化的替代轨迹。
