CONICET | Buscador de Institutos y Recursos Humanos

Abstract?Gene expression is a necessary step for memoryre-stabilization after retrieval, a process known as reconsolidation.Histone acetylation is a fundamental mechanisminvolved in epigenetic regulation of gene expression andhas been implicated in memory consolidation. However,few studies are available in reconsolidation, all of them invertebrate models. Additionally, the recruitment of histoneacetylation as a function of different memory strengthshas not been systematically analyzed before. Here we studiedthe role of histone acetylation in reconsolidation using awell-characterized memory model in invertebrate, the context-signal memory in the crab Chasmagnathus. Firstly, wefound an increase in histone H3 acetylation 1 h after memoryreactivation returning to basal levels at 3 h. Strikingly, thisincrement was only detected during reconsolidation of along-term memory induced by a strong training of 30 trials,but not for a short-term memory formed by a weak trainingof five trials or for a long-term memory induced by a standardtraining of 15 trials. Furthermore, we showed that aweak memory which was enhanced during consolidationby histone deacetylases inhibition, also recruited histoneH3 acetylation in reconsolidation as the strong trainingdoes. Accordingly, we found the first evidence that theadministration of a histone acetyl transferase inhibitor duringmemory reconsolidation impairs long-term memoryre-stabilization. Finally, we found that strong training memory,at variance with the standard training memory, wasresistant to extinction, indicating that such strong traininginduced in fact a stronger memory. In conclusion, theresults presented here support that the participation of histoneacetylation during reconsolidation is an evolutionaryconserved feature and constitutes a specific molecular characteristicof strong memories. 2012 IBRO. Published byElsevier Ltd. All rights reserved.