Coupling of energy metabolism and synaptic transmission at the transcriptional level: role of nuclear respiratory factor 1 in regulating both cytochrome c oxidase and NMDA glutamate receptor subunit genes.
Neuronal activity and energy metabolism are tightly coupled processes. Regions high in neuronal activity, especially of the glutamatergic type, have high levels of cytochrome c oxidase (COX). Perturbations in neuronal activity affect the expressions of COX and glutamatergic NMDA receptor subunit 1 (NR1). The present study sought to test our hypothesis that the coupling extends to the transcriptional level, whereby NR1 and possibly other NR subunits and COX are coregulated by the same transcription factor, nuclear respiratory factor 1 (NRF-1), which regulates all COX subunit genes. By means of multiple approaches, including in silico analysis, electrophoretic mobility shift and supershift assays, in vivo chromatin immunoprecipitation, promoter mutations, and real-time quantitative PCR, NRF-1 was found to functionally bind to the promoters of Grin 1 (NR1), Grin 2b (NR2b) and COX subunit genes, but not of Grin2a and Grin3a genes. These transcripts were upregulated by KCl and downregulated by tetrodotoxin (TTX) in cultured primary neurons. However, silencing of NRF-1 with small interference RNA blocked the upregulation of Grin1, Grin2b, and COX induced by KCl, and overexpression of NRF-1 rescued these transcripts that were suppressed by TTX. NRF-1 binding sites on Grin1 and Grin2b genes are also highly conserved among mice, rats, and humans. Thus, NRF-1 is an essential transcription factor critical in the coregulation of NR1, NR2b, and COX, and coupling exists at the transcriptional level to ensure coordinated expressions of proteins important for synaptic transmission and energy metabolism.
Dhar
Shilpa S
SS
Department of Cell Biology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
Wong-Riley
Margaret T T
MT
D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D047369:Chromatin Immunoprecipitation / Q000379:methods; D003576:Electron Transport Complex IV / Q000235:genetics*; D024202:Electrophoretic Mobility Shift Assay / Q000379:methods; D004734:Energy Metabolism / Q000502:physiology*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics; D006801:Humans; D051379:Mice; D009154:Mutation / Q000502:physiology; D009447:Neuroblastoma; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D051266:Nuclear Respiratory Factor 1 / Q000378:metabolism*; D011189:Potassium Chloride / Q000494:pharmacology; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D051381:Rats; D016194:Receptors, N-Methyl-D-Aspartate / Q000235:genetics*; D026941:Sodium Channel Blockers / Q000494:pharmacology; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D013779:Tetrodotoxin / Q000494:pharmacology; D014162:Transfection / Q000379:methods
C409466:NR1 NMDA receptor; D051266:Nuclear Respiratory Factor 1; D021122:Protein Subunits; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D016194:Receptors, N-Methyl-D-Aspartate; D026941:Sodium Channel Blockers; D013779:Tetrodotoxin; D011189:Potassium Chloride; D003576:Electron Transport Complex IV