Galton Riley, Fejes-Toth Katalin, Bronner Marianne E
Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA.
Sci Adv. 2022 Aug 12;8(32):eabn1441. doi: 10.1126/sciadv.abn1441. Epub 2022 Aug 10.
Across Metazoa, Piwi proteins play a critical role in protecting the germline genome through piRNA-mediated repression of transposable elements. In vertebrates, activity of Piwi proteins and the piRNA pathway was thought to be gonad specific. Our results reveal the expression of Piwil1 in a vertebrate somatic cell type, the neural crest. Piwil1 is expressed at low levels throughout the chicken neural tube, peaking in neural crest cells just before the specification event that enables epithelial-to-mesenchymal transition (EMT) and migration into the periphery. Loss of Piwil1 impedes neural crest specification and emigration. Small RNA sequencing reveals somatic piRNAs with sequence signatures of an active ping-pong loop. RNA-seq and functional experiments identify the transposon-derived gene ERNI as Piwil1's target in the neural crest. ERNI, in turn, suppresses to precisely control the timing of neural crest specification and EMT. Our data provide mechanistic insight into a novel function of the piRNA pathway as a regulator of somatic development in a vertebrate species.
在整个后生动物中，Piwi蛋白通过piRNA介导的转座元件抑制作用，在保护生殖系基因组方面发挥着关键作用。在脊椎动物中，Piwi蛋白和piRNA途径的活性被认为具有性腺特异性。我们的研究结果揭示了Piwil1在脊椎动物体细胞类型——神经嵴中的表达。Piwil1在鸡的整个神经管中低水平表达，在神经嵴细胞中达到峰值，此时恰好是上皮-间充质转化（EMT）并迁移到外周的特化事件发生之前。Piwil1的缺失会阻碍神经嵴的特化和迁移。小RNA测序揭示了具有活跃乒乓环序列特征的体细胞piRNA。RNA测序和功能实验确定转座子衍生基因ERNI是神经嵴中Piwil1的靶标。反过来，ERNI抑制……以精确控制神经嵴特化和EMT的时间。我们的数据为piRNA途径作为脊椎动物物种体细胞发育调节因子的新功能提供了机制上的见解。
