Program in Molecular Medicine; Department of Biochemistry and Molecular Pharmacology
Animals; Down-Regulation; Electric Stimulation; Electrophysiology; Growth Hormone; Hippocampus; Humans; Long-Term Potentiation; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Neuronal Plasticity; Protein Biosynthesis; Proteomics; Proto-Oncogene Proteins c-jun; RNA Precursors; RNA, Messenger; Recombinant Proteins; Synapses; Transcription Factors; Transcription, Genetic; mRNA Cleavage and Polyadenylation Factors
Life Sciences | Medicine and Health Sciences
Cytoplasmic polyadenylation element binding protein 1 (CPEB-1) resides at postsynaptic sites in hippocampal neurons in which it controls polyadenylation-induced translation. CPEB-1 knock-out (KO) mice display defects in some forms of synaptic plasticity and hippocampal-dependent memories. To identify CPEB-1-regulated mRNAs, we used proteomics to compare polypeptides in wild-type (WT) and CPEB-1 KO hippocampus. Growth hormone (GH) was reduced in the KO hippocampus, as were the GH signaling molecules phospho-JAK2 and phospho-STAT3. GH mRNA and pre-mRNA were reduced in the KO hippocampus, suggesting that CPEB-1 controls GH transcription. The transcription factor c-Jun, which binds the GH promoter, was also reduced in the KO hippocampus, as was its ability to coimmunoprecipitate chromatin containing the GH promoter. CPEB-1 binds c-Jun 3' untranslated region CPEs in vitro and coimmunoprecipitates c-Jun RNA in vivo. GH induces long-term potentiation (LTP) when applied to hippocampal slices from WT and CPEB-1 KO mice, but the magnitude of LTP induced by GH in KO mice is reduced. Pretreatment with GH did not reverse the LTP deficit observed in KO mice after theta-burst stimulation (TBS). Cordycepin, an inhibitor of polyadenylation, disrupted LTP induced by either GH application or TBS. Finally, GH application to hippocampal slices induced JAK2 phosphorylation in WT but not KO animals. These results indicate that CPEB-1 control of c-Jun mRNA translation regulates GH gene expression and resulting downstream signaling events (e.g., synaptic plasticity) in the mouse hippocampus.
DOI of Published Version
J Neurosci. 2008 Aug 20;28(34):8502-9. Link to article on publisher's site
The Journal of neuroscience : the official journal of the Society for Neuroscience
Zearfoss, Nancy R.; Alarcon, Juan Marcos; Trifilieff, Pierre; Kandel, Eric; and Richter, Joel D., "A molecular circuit composed of CPEB-1 and c-Jun controls growth hormone-mediated synaptic plasticity in the mouse hippocampus" (2008). Open Access Articles. 2068.