Involvement of deltaCalcium/calmodulin-dependent protein kinase II in persistent forms of memory

GISELA ZALCMAN; NOEL FEDERMAN; ANA FISZBEIN; ARTURO ROMANO

Congreso; 9th IBRO World Congress of Neuroscience; 2015

Calcium/calmodulin-dependent protein kinase II (CaMKII) is an abundant synaptic signaling molecule that is essential for both memory formation and synaptic potentiation. In mammals, CaMKII exists in multiple isoforms that are the product of four closely related genes: α, β, γ, and δ. Little information is known about the role of the δCaMKII in memory processes. In a previous study, we showed that Camk2d mRNA levels in the mice hippocampus were specifically induced 3h after strong ?Novel Object Recognition? (NOR) training, but not after standard training. Strong and standard training induce long-term-memory (LTM) formation, but only the strong protocol induces a persistent form of recognition memory which can be assessed 7 days after training. Chromatin of the Camk2d gene promoter is acetylated only after strong training in a NF-кB dependent manner. These data support that Camk2d gene is specifically expressed for the formation of persistent forms of recognition memory. In the present work, we carried out experiments aimed at determining the epigenetic regulation, expression and role of CamK2d on recognition memory. In the first place, we measured nucleosome remodeling at the Camk2d promoter during NOR memory consolidation. Secondly, to study the requirement of δCaMKII in memory we knocked down δCaMKII expression with an oligodeoxynucleotide antisense to its mRNA immediately after strong training and tested the memory effect 24hs and 1 week after training. We found that NOR memory was intact 24hs after training but it was impaired when assessed 1 week later, indicating that δCamKII knock-down immediately after training affects the maintenance of persistent forms of recognition memories. Finally, we measured δCamKII mRNA expression at longer time-points, outside the memory consolidation window. Here we present the preliminary results. All these data support a key role of δCaMKII isoform in persistent forms of memory.