Transcriptome and Mutant Analysis of Neuronal Genes for Memory Formation and Retrieval in Caenorhabditis elegans

Although it is generally believed that the formation and retrieval of memory require distinct sets of genes, little is known about the identity and temporal specificity of genes that act at different memory stages. Here we characterize the transcriptomes for the formation and retrieval of stress-induced aversive memory in the nematode Caenorhabditis elegans. Our RNA-sequencing analysis show that neuronal genes for calcium homeostasis, membrane excitability, synaptic function and signaling are progressively activated during the formation of aversive memory. Stage-specific transcriptomes further reveal that memory formation and retrieval display distinct gene activation patterns. We carried out a candidate screen of mutants for these memory genes and verified the temporal requirement of memory function for several of them. Further in-depth characterization of casy-1/calsyntenin show that while the short CASY-1B isoform acts in memory retrieval, the long CASY-1A isoform functions during memory formation, and its shed extracellular N-terminus fragment is likely a critical signal for memory regulation. Our work uncovers gene expression patterns associated with distinct memory stages and provides a foundation for future mechanistic interrogation of memory functions. To investigate the important neuronal genes for stress-induced aversive learning and memory, we used atp-2 RNAi to disrupt core cellular function.We then perform gene expression profiling in memory formation, retrieval and during memory formation.

尽管普遍认为记忆的形成与提取需要不同的基因集合，但对于在不同记忆阶段发挥作用的基因的身份及其时序特异性，目前仍知之甚少。本研究对秀丽隐杆线虫（Caenorhabditis elegans）中应激诱导的厌恶性记忆的形成与提取过程的转录组进行了表征。我们的RNA测序（RNA-sequencing）分析显示，参与钙稳态、膜兴奋性、突触功能及信号传导的神经元基因在厌恶性记忆形成过程中被逐步激活。阶段特异性转录组进一步揭示，记忆形成与提取展现出截然不同的基因激活模式。我们针对这些记忆相关基因开展了突变体候选筛选，并验证了其中数个基因在记忆功能中的时序必要性。针对casy-1/钙连蛋白（calsyntenin）的进一步深入表征显示，短亚型CASY-1B参与记忆提取，而长亚型CASY-1A在记忆形成过程中发挥功能，其被分泌的细胞外N端片段可能是记忆调控的关键信号。本研究揭示了与不同记忆阶段相关的基因表达模式，为未来解析记忆功能的机制奠定了基础。为探究应激诱导的厌恶性学习与记忆相关的重要神经元基因，我们使用atp-2 RNA干扰（RNAi）破坏核心细胞功能。随后我们在记忆形成、记忆提取以及记忆形成阶段开展了基因表达谱分析。