Engram-specific transcriptome profiling of contextual memory consolidation

Sparse populations of neurons in the dentate gyrus (DG) of the hippocampus are causally implicated in the encoding of contextual fear memories. However, engram-specific molecular mechanisms underlying memory consolidation remain largely unknown. Here we perform unbiased RNA sequencing of DG engram neurons 24h after contextual fear conditioning to identify transcriptome changes specific to memory consolidation. DG engram neurons exhibit a highly distinct pattern of gene expression, in which CREB-dependent transcription features prominently (P=6.2x10-13), including Atf3 (P=2.4x10-41), Penk (P=1.3x10-15), and Kcnq3 (P=3.1x10-12). Moreover, we validate the functional relevance of the RNAseq findings by establishing the causal requirement of intact CREB function specifically within the DG engram during memory consolidation, and identify a novel group of CREB target genes involved in the encoding of long-term memory. Overall design: Biological replicates: Fear conditioned: n=14, No shock controls: n=4, Home cage controls:n=3. The contents 10 dVenus+ and 10 dVenus- cells were aspirated from each animal (biological replicate)

海马体齿状回（dentate gyrus, DG）中的稀疏神经元群体与情境恐惧记忆的编码存在因果关联。然而，支撑记忆巩固的印迹细胞（engram）特异性分子机制目前仍尚未完全阐明。本研究对情境恐惧条件化处理24小时后的DG印迹细胞开展无偏RNA测序，以鉴定与记忆巩固相关的特异性转录组变化。DG印迹细胞呈现出高度独特的基因表达谱，其中CREB依赖的转录过程显著富集（P=6.2×10^-13），涉及Atf3（P=2.4×10^-41）、Penk（P=1.3×10^-15）及Kcnq3（P=3.1×10^-12）。此外，本研究通过验证记忆巩固期间DG印迹细胞内完整CREB功能的因果必要性，证实了RNA测序结果的功能相关性，并鉴定出一组参与长期记忆编码的新型CREB靶基因。实验整体设计：生物学重复分组为：恐惧条件化组n=14、无电击对照组n=4、正常饲养对照组n=3；每只动物（生物学重复样本）中均分离获取10个dVenus阳性细胞与10个dVenus阴性细胞用于后续实验。