Laboratory of RNA Function, Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, Japan.
Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan.
EMBO Rep. 2021 Jul 5;22(7):e51342. doi: 10.15252/embr.202051342. Epub 2021 May 11.
PIWI-interacting RNAs (piRNAs) guide PIWI proteins to silence transposable elements and safeguard fertility in germ cells. Many protein factors required for piRNA biogenesis localize to perinuclear ribonucleoprotein (RNP) condensates named nuage, where target silencing and piRNA amplification are thought to occur. In mice, some of the piRNA factors are found in discrete cytoplasmic foci called processing bodies (P-bodies). However, the dynamics and biological significance of such compartmentalization of the piRNA pathway remain unclear. Here, by analyzing the subcellular localization of functional mutants of piRNA factors, we show that piRNA factors are actively compartmentalized into nuage and P-bodies in silkworm cells. Proper demixing of nuage and P-bodies requires target cleavage by the PIWI protein Siwi and ATP hydrolysis by the DEAD-box helicase BmVasa, disruption of which leads to promiscuous overproduction of piRNAs deriving from non-transposable elements. Our study highlights a role of dynamic subcellular compartmentalization in ensuring the fidelity of piRNA biogenesis.
PIWI 相互作用 RNA（piRNAs）指导 PIWI 蛋白沉默转座元件并保护生殖细胞的活力。许多参与 piRNA 生物发生的蛋白质因子定位于核周核糖核蛋白（RNP）凝聚体，称为 nuage，人们认为靶基因沉默和 piRNA 扩增发生在那里。在小鼠中，一些 piRNA 因子存在于称为处理体（P-body）的离散细胞质焦点中。然而，piRNA 途径的这种区室化的动力学和生物学意义仍不清楚。在这里，通过分析 piRNA 因子的功能突变体的亚细胞定位，我们表明 piRNA 因子在蚕细胞中被主动分隔到 nuage 和 P 体中。nuage 和 P 体的正确分离需要 PIWI 蛋白 Siwi 对靶标进行切割和 DEAD 盒解旋酶 BmVasa 的 ATP 水解，破坏这两者会导致非转座元件衍生的 piRNA 无差别过量产生。我们的研究强调了动态亚细胞区室化在确保 piRNA 生物发生保真度中的作用。
