MRC London Institute of Medical Sciences, Du Cane Road, London, W12 0NN, UK.
Institute of Clinical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK.
BMC Biol. 2018 Sep 18;16(1):103. doi: 10.1186/s12915-018-0571-y.
piRNAs have a constitutive role in genome defence by silencing transposable elements in the germline. In the nematode Caenorhabditis elegans, piRNAs also induce epigenetic silencing of transgenes, which can be maintained for many generations in the absence of the piRNA pathway. The role of multi-generational epigenetic inheritance in adaptation to the environment is unknown.
Here, we show that piRNA biogenesis is downregulated in response to a small increase in temperature. Some effects on gene expression persist into subsequent generations and are associated with a negative fitness cost. We show that simultaneous infection with pathogenic bacteria suppresses downregulation of the piRNA pathway in response to increased temperature. This effect is associated with increased fitness of progeny of infected animals in subsequent generations.
Our results show that the piRNA pathway integrates inputs from the environment to establish intergenerational responses to environmental conditions, with important consequences for the fitness of the subsequent generation.
piRNA 在通过沉默生殖系中的转座元件来防御基因组方面起着组成性作用。在线虫秀丽隐杆线虫中，piRNA 还诱导转基因的表观遗传沉默，在没有 piRNA 途径的情况下，这种沉默可以维持许多代。多代表观遗传遗传在适应环境中的作用尚不清楚。
在这里，我们表明 piRNA 的生物发生在响应小的温度升高时下调。一些对基因表达的影响持续到后代，并与负适合度成本相关。我们表明，同时感染致病性细菌会抑制 piRNA 途径对温度升高的反应下调。这种效应与感染动物后代在随后的几代中的适应性增加有关。
我们的结果表明，piRNA 途径整合了来自环境的输入，以建立对环境条件的跨代反应，这对随后一代的适应性有重要影响。
