EN
It is now firmly established that long-lasting synaptic plasticity involves dramatic changes in gene expression occurring under the influence of specific signaling pathways and transcription factors. Numerous studies have shown that DNA and histone epigenetic modifications play key roles in neuronal plasticity. Recent studies in non-neuronal cells, indicated the existence of epigenetic mechanism of yet another class, related to the nuclei structural remodeling and very poorly understood in neurons. Therefore, we decided to study the ultrastructure of the cell nuclei in the hippocampal dentate gyrus granule neurons upon seizures induced by kainic acid, an analog of glutamate. Under these conditions the granular neurons instead of degradation, undergo an intensive plasticity phenomena. We found that seizures led to rapid and dramatic enlargement and striking reorganization of internal component-structures of interchromatin granule clusters (IGCs) in granular cell’s nucleus. Moreover, unlike IGCs of control animals, the reorganized IGCs contained activated RNA polymerase II CTD phosphoepitopes. These observations may suggest involvement of IGC in activity-dependent transcription events in neurons.