C EBP IS AN IMMEDIATE-EARLY GENE REQUIRED FOR THE CONSOLIDATION OF LONG-TERM FACILITATION IN APLYSIA/

The consolidation of long-term memory requires protein and mRNA synthe sis. A similar requirement has been demonstrated for learning-related synaptic plasticity in the gill-withdrawal reflex of Aplysia. The mono synaptic component of this reflex can be reconstituted in vitro, where it undergoes both short- and long-term increases in synaptic strength in response to serotonin (5-HT), a neurotransmitter released during b ehavioral sensitization, a simple form of learning. As with sensitizat ion, the long-term synaptic modification is characterized by a brief c onsolidation period during which gene expression is required. We f ind that during this phase, the transcription factor Aplysia CCAAT enhanc er-binding protein (ApC/EBP) is induced rapidly by 5-HT and by cAMP, e ven in the presence of protein synthesis inhibitors. Blocking the func tion of ApC/EBP blocks long-term facilitation selectively without affe cting the short-term process. These data indicate that cAMP-inducible immediate-early genes have an essential role in the consolidation of s table long-term synaptic plasticity in Aplysia.