Nerve growth factor regulates tyrosine hydroxylase gene transcription through a nucleoprotein complex that contains c-Fos.
We have studied nerve growth factor (NGF) regulation of the expression of the tyrosine hydroxylase (TH) gene in PC12 cells. The TH gene encodes the initial and rate-limiting enzyme of the catecholamine biosynthetic pathway. We show that the TH gene is transiently transcriptionally induced by a mechanism reliant on new protein synthesis during 1-2 hr of NGF stimulation, a time following the induction of the c-fos gene at 15 min post-NGF treatment. A potential regulatory sequence located within the TH gene promoter, the TH-FSE, shares homology to a known regulatory element, the fat-specific element (FSE), which is found upstream from genes activated during adipocyte differentiation and binds the Fos-Jun transcription factor complex. We show that the TH-FSE DNA sequence elevates the basal level of transcription from the rat TH promoter and is required for NGF inducibility. This DNA element binds authentic Fos-Jun products produced abundance during NGF stimulation and by in vitro translation. We demonstrate further that the TH-FSE can bind proteins present in PC12 nuclear extracts in a sequence-specific manner. The DNA/nucleoprotein complex that forms increases in abundance during NGF stimulation and reaches a maximum level at 4 hr of treatment. Antibody inhibition studies utilizing an anti-Fos antibody indicate that Fos and/or Fos-related antigen(s) associate with the TH-FSE and suggest that the Fos protein family contributes to the regulation of TH in vivo. These results support a model in which NGF-induced immediate early genes, including c-Fos, contribute to the regulation of delayed early genes such as TH and thereby control neuronal differentiation.
Gizang-Ginsberg
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Department of Biochemistry, New York University Medical Center, New York 10016.
Ziff
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EB
D000818:Animals; D001483:Base Sequence; D002454:Cell Differentiation; D002460:Cell Line; D015971:Gene Expression Regulation, Enzymologic; D007700:Kinetics; D008969:Molecular Sequence Data; D009414:Nerve Growth Factors / Q000494:pharmacology*; D009698:Nucleoproteins / Q000378:metabolism; D011401:Promoter Regions, Genetic; D014176:Protein Biosynthesis; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos; D051381:Rats; D012045:Regulatory Sequences, Nucleic Acid; D012689:Sequence Homology, Nucleic Acid; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic; D014446:Tyrosine 3-Monooxygenase / Q000235:genetics* / Q000378:metabolism
D009414:Nerve Growth Factors; D009698:Nucleoproteins; D011518:Proto-Oncogene Proteins; D016760:Proto-Oncogene Proteins c-fos; D014157:Transcription Factors; D014446:Tyrosine 3-Monooxygenase