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piwi相互作用的RNA (piRNA)通路控制动物生殖细胞中转座子的表达，从而确保了世代基因组的稳定性。在果蝇中，piRNA是通过母系血统代际遗传的，这在确定piRNA源位点和沉默子细胞中I-和p元素方面表现出了重要意义。母体遗传的Piwi蛋白在合子基因组激活之前进入早期胚胎的体细胞核，并在完成胚胎发育所需的大约一半时间内持续在其中。为了研究piRNA通路在胚胎体细胞中的作用，我们创造了一种条件不稳定Piwi蛋白。这使得母体沉积的Piwi可以在30分钟内从新产的胚胎中清除，而且远远早于合子转录的激活。随着时间的推移，对RNA和蛋白质谱的检测，以及与H3K9me3沉积模式的相关性，表明母体沉积的Piwi在发育胚胎体细胞中减弱合子转座子表达的作用。特别是，针对roo(其表达主要局限于胚胎发育)的piRNAs的稳定沉积导致了主动roo插入时瞬时异色标记的沉积。我们假设roo，一种非常成功的移动元素，可能在胚胎体细胞中采用了一种表达方式，以逃避生殖细胞中的沉默。 The PIWI-interacting RNA (piRNA) pathway controls transposon expression in animal germ cells, thereby ensuring genome stability over generations. In Drosophila, piRNAs are intergenerationally inherited through the maternal lineage, and this has demonstrated importance in the specification of piRNA source loci and in silencing of I- and P-elements in the germ cells of daughters. Maternally inherited Piwi protein enters somatic nuclei in early embryos prior to zygotic genome activation and persists therein for roughly half of the time required to complete embryonic development. To investigate the role of the piRNA pathway in the embryonic soma, we created a conditionally unstable Piwi protein. This enabled maternally deposited Piwi to be cleared from newly laid embryos within 30 minutes and well ahead of the activation of zygotic transcription. Examination of RNA and protein profiles over time, and correlation with patterns of H3K9me3 deposition, suggests a role for maternally deposited Piwi in attenuating zygotic transposon expression in somatic cells of the developing embryo. In particular, robust deposition of piRNAs targeting roo, an element whose expression is mainly restricted to embryonic development, results in the deposition of transient heterochromatic marks at active roo insertions. We hypothesize that roo, an extremely successful mobile element, may have adopted a lifestyle of in the embryonic soma to evade silencing in germ cells. PMID: 34236313 DOI: 10.7554/eLife.68573  文章来源原创；如有侵权请及时联系PaperRSS小编删除，转载请注明来源。 温馨提示： 为方便PaperRSS粉丝们科研、就业等话题交流。我们根据10多个专业方向（植物、医学、药学、人工智能、化学、物理、财经管理、体育等），特建立了30个国内外博士交流群。群成员来源欧美、日韩、新加坡、清华北大、中科院等全球名校。 |
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