Chemogenetic evidence that rapid neuronal de novo protein synthesis is required for consolidation of long-term memory

Prerana Shrestha; Pinar Ayata; Pedro Herrero-Vidal; Francesco Longo; Alexandra Gastone; Joseph E. Ledoux; Nathaniel Heintz; Eric Klann

As a result of phosphorylation of eIF2α, proteins whose transcripts harbor uORFs, specifically ATF4 and 184 GADD34, accumulated and remained at higher levels compared to control until 3h (Fig. 2e) . GADD34 is the 185 regulatory subunit of the eIF2α phosphatase 17 , and the negative feedback due to increased GADD34 levels 186 combined with the degradation of iPKR by NS3/4 protease at 3h time point might be responsible for reduced synthesis 29, 30 . To determine whether chemogenetic inhibition of pan-neuronal protein synthesis influences persistent cortical and thalamic input-specific synaptic potentiation in principal excitatory neurons within LA 37, 232 38 . Thus, we asked whether de novo protein synthesis in CamK2α-positive principal neurons in LA is necessary 233 for aversive memory consolidation. We virally delivered CamK2α.Cre.EGFP into the bilateral LA of iPKR mice 234 and control mice (Fig. 4a) . Phosphorylation of eIF2α was increased specifically in CamK2α.iPKR neurons 235 compared to wild-type mice and non-EGFP positive neurons in the same animals ( Fig. 4b) with a 236 corresponding decrease in de novo translation (Fig. 4c ) upon ASV administration. CamK2α.iPKR mice were 237 threat conditioned as previously and centrally infused with ASV immediately after training (Fig. 4d ).