APLYSIA CREB2 REPRESSES LONG-TERM FACILITATION - RELIEF OF REPRESSIONCONVERTS TRANSIENT FACILITATION INTO LONG-TERM FUNCTIONAL AND STRUCTURAL-CHANGE

The switch from short- to long-term facilitation induced by behavioral sensitization in Aplysia involves CREB-like proteins, as well as the immediate-early gene ApC/EBP. Using the bZIP domain of ApC/EBP in a tw o-hybrid system, we have cloned ApCREB2, a transcription factor consti tutively expressed in sensory neurons that resembles human CREB2 and m ouse ATF4. ApCREB2 represses ApCREB-1-mediated transcription in F9 cel ls. Injection of anti-ApCREB2 antibodies into Aplysia sensory neurons causes a single pulse of serotonin (5-HT), which induces only short-te rm facilitation lasting minutes, to evoke facilitation lasting more th an 1 day. This facilitation has the properties of long-term facilitati on: it requires transcription and translation, induces the growth of n ew synaptic connections, and occludes further facilitation by five pul ses of 5-HT.