Animals face both external and internal dangers: pathogens threaten from the environment, and unstable genomic elements threaten from within. C. elegans protects itself from pathogens by “reading” bacterial small RNAs, using this information to both induce avoidance and transmit memories for four generations. Here, we found that memories can be transferred from either lysed animals or from conditioned media to naive animals via Cer1 retrotransposon-encoded virus-like particles. Moreover, Cer1 functions internally at the step of transmission of information from the germline to neurons and is required for learned avoidance. The presence of the Cer1 retrotransposon in wild C. elegans strains correlates with the ability to learn and inherit small-RNA-induced pathogen avoidance. Together, these results suggest that C. elegans has co-opted a potentially dangerous retrotransposon to instead protect itself and its progeny from a common pathogen through its inter-tissue signaling ability, hijacking this genomic element for its own adaptive immunity benefit.

动物面临外部和内部危险：病原体来自环境威胁，不稳定的基因组元素来自内部威胁。秀丽隐杆线虫通过“读取”细菌小 RNA 来保护自己免受病原体的侵害，利用这些信息来诱导回避和将记忆传递四代。在这里，我们发现记忆可以通过Cer1逆转录转座子编码的病毒样颗粒从裂解的动物或条件培养基转移到幼稚动物。此外，Cer1在从生殖系到神经元的信息传输步骤中内部发挥作用，并且是学习回避所必需的。野生秀丽隐杆线虫中Cer1逆转录转座子的存在菌株与学习和继承小RNA诱导的病原体避免的能力相关。总之，这些结果表明，秀丽隐杆线虫已经选择了一种具有潜在危险的反转录转座子，通过其组织间信号传导能力来保护自己及其后代免受常见病原体的侵害，劫持这种基因组元件以获得自身的适应性免疫益处。