Intergenerational metabolic priming by sperm piRNAs. Intergenerational metabolic priming by sperm piRNAs

Preconception parental environment can reproducibly program offspring phenotype without altering the DNA sequence, yet the mechanisms underpinning this ‘epigenetic inheritance’ remains elusive. Here, we demonstrate the existence of an intact piRNA-pathway in mature Drosophila sperm and show that pathway modulation alters offspring gene transcription in a sequence-specific manner. We map a dynamic small RNA content in developing sperm and find that the mature sperm carry a highly distinct small RNA cargo. By biochemical pulldown, we identify a small RNA subset bound directly to piwi protein. And, we show that piRNA-pathway controlled sperm small RNAs are linked to target gene repression in offspring. Critically, we find that full piRNA-pathway dosage is necessary for the intergenerational metabolic and transcriptional reprogramming events triggered by high paternal dietary sugar. These data provide a direct link between regulation of endogenous mature sperm small RNAs and transcriptional programming of complementary sequences in offspring. Thus, we identify a novel mediator of paternal intergenerational epigenetic inheritance. Overall design: Drosophila melanogaster small RNA and mRNA samples with differing library preparations, tissue, and genotypes.

受孕前的父母环境可在不改变DNA序列的前提下，可重复地调控子代的表型，然而支撑这一‘表观遗传（epigenetic inheritance）’的机制仍尚不明确。本研究证实成熟果蝇精子中存在完整的piRNA（Piwi相互作用RNA）通路，并证明该通路的调控可通过序列特异性的方式改变子代的基因转录。我们对发育中精子的动态小RNA表达谱进行了绘制，发现成熟精子携带一组高度独特的小RNA负载组分。通过生化下拉实验，我们鉴定出了一组直接结合Piwi蛋白的小RNA子集。此外，我们发现受piRNA通路调控的精子小RNA与子代中的靶基因沉默存在关联。至关重要的是，我们发现完整的piRNA通路活性是父本高糖饮食所诱导的代际代谢与转录重编程事件所必需的。本研究数据为内源性成熟精子小RNA的调控与子代中互补序列的转录编程之间建立了直接联系。因此，我们鉴定出了一种介导父本代际表观遗传的新型因子。实验整体设计：采用不同建库方式、组织类型与基因型的黑腹果蝇（Drosophila melanogaster）小RNA与mRNA样本。