cAMP response element-binding protein 1 feedback loop is necessary for consolidation of long-term synaptic facilitation in Aplysia.
The transcription factor cAMP response element (CRE)-binding protein (CREB) plays an essential role in the induction of many forms of long-term synaptic plasticity. Levels of CREB1, the Aplysia homolog of CREB, show sustained elevations for several hours after the induction of long-term synaptic facilitation (LTF). Furthermore, CREB1 binds to the promoter of its own gene. These results suggest the existence of a CREB1-positive feedback loop that contributes to the consolidation of LTF. In the present study, we provide a detailed, quantitative characterization of the dynamics of CREB1 mRNA and protein as well as CREB1 phosphorylation after LTF induction. Injections of CRE oligonucleotides prevented the increase in CREB1 in response to 5-HT, corroborating the existence of the CREB1 feedback loop. This loop probably sustains CRE-dependent gene transcription, which remains elevated for at least 12 h after LTF induction. LTF is blocked by injection of CREB1 antibody after the induction phase, suggesting that the CREB1-positive feedback is required for consolidation of LTF.
Liu
Rong-Yu
RY
Department of Neurobiology and Anatomy, W. M. Keck Center for the Neurobiology of Learning and Memory, The University of Texas Medical School at Houston, Houston, Texas 77030, USA.
Fioravante
Diasinou
D
Shah
Shreyansh
S
Byrne
John H
JH
D000818:Animals; D001048:Aplysia; D018920:Coculture Techniques; D017362:Cyclic AMP Response Element-Binding Protein / Q000737:chemistry / Q000502:physiology*; D025461:Feedback, Physiological / Q000502:physiology*; D017774:Long-Term Potentiation / Q000502:physiology*; D009419:Nerve Tissue Proteins / Q000502:physiology*; D009475:Neurons, Afferent / Q000502:physiology; D040681:Structural Homology, Protein; D013569:Synapses / Q000502:physiology*
C115163:CREB1 protein, human; D017362:Cyclic AMP Response Element-Binding Protein; D009419:Nerve Tissue Proteins