Calcium influx via the NMDA receptor induces immediate early gene transcription by a MAP kinase/ERK-dependent mechanism.
The regulation of gene expression by neurotransmitters is likely to play a key role in neuroplasticity both during development and in the adult animal. Therefore, it is important to determine the mechanisms of neuronal gene regulation to understand fully the mechanisms of learning, memory, and other long-term adaptive changes in neurons. The neurotransmitter glutamate stimulates rapid and transient induction of many genes, including the c-fos proto-oncogene. The c-fos promoter contains several critical regulatory elements, including the serum response element (SRE), that mediate glutamate-induced transcription in neurons; however, the mechanism by which the SRE functions in neurons has not been defined. In this study, we sought to identify transcription factors that mediate glutamate induction of transcription through the SRE in cortical neurons and to elucidate the mechanism(s) of transcriptional activation by these factors. To facilitate this analysis, we developed an improved calcium phosphate coprecipitation procedure to transiently introduce DNA into primary neurons, both efficiently and consistently. Using this protocol, we demonstrate that the transcription factors serum response factor (SRF) and Elk-1 can mediate glutamate induction of transcription through the SRE in cortical neurons. There are at least two distinct pathways by which glutamate signals through the SRE: an SRF-dependent pathway that can operate in the absence of Elk and an Elk-dependent pathway. Activation of the Elk-dependent pathway of transcription seems to require phosphorylation of Elk-1 by extracellular signal-regulated kinases (ERKs), providing evidence for a physiological function of ERKs in glutamate signaling in neurons. Taken together, these findings suggest that SRF, Elk, and ERKs may have important roles in neuroplasticity.
Xia
Z
Z
Department of Neurology, Children's Hospital, Boston, Massachusetts 02115, USA.
Dudek
H
H
Miranti
C K
CK
Greenberg
M E
ME
D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism*; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000502:physiology; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000378:metabolism; D017781:Genes, Immediate-Early; D018698:Glutamic Acid / Q000494:pharmacology; D009419:Nerve Tissue Proteins / Q000502:physiology*; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D009687:Nuclear Proteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051381:Rats; D020794:Receptor Protein-Tyrosine Kinases / Q000502:physiology*; D036143:Receptor, EphA8; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*; D011994:Recombinant Proteins; D026362:Serum Response Factor; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014162:Transfection; D050807:ets-Domain Protein Elk-1
D004268:DNA-Binding Proteins; C494114:Elk1 protein, rat; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D016194:Receptors, N-Methyl-D-Aspartate; D011994:Recombinant Proteins; D026362:Serum Response Factor; D015534:Trans-Activators; D014157:Transcription Factors; D050807:ets-Domain Protein Elk-1; D018698:Glutamic Acid; D020794:Receptor Protein-Tyrosine Kinases; D036143:Receptor, EphA8; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002118:Calcium