Nerve growth factor regulates adrenergic expression.
The mechanism by which nerve growth factor (NGF) regulates adrenergic expression was examined in PC-12 cells transfected with a rat phenylethanolamine N-methyl-transferase (PNMT) promoter-luciferase reporter gene construct pGL3RP893. NGF treatment increased PNMT promoter-driven luciferase activity in a dose- and time-dependent manner. Induction was attenuated by inhibition of the extracellular signal-regulated kinase mitogen-activated protein kinase (MAPK) pathway ( approximately 60%) but not by inhibition of the protein kinase A (PKA), protein kinase C, phosphoinositol kinase, or p38 MAPK pathways. Deletion PNMT promoter-luciferase reporter gene constructs showed that the NGF-responsive sequences lay within the proximal -392 base pairs (bp) of PNMT promoter, wherein binding elements for Egr-1 (-165 bp) and Sp1 (-48 bp) reside. Western analysis further showed that NGF increased nuclear levels of Egr-1, but not Sp1 or the catalytic subunit of PKA. Gel mobility shift assays showed increased potential for Egr-1, but not Sp1, protein-DNA binding complex formation. Mutation of either the Egr-1 or Sp1 binding sites in the PNMT promoter attenuated NGF activation. NGF, combined with pituitary adenylyl cyclase-activating protein (PACAP), another PNMT transcriptional activator, cooperatively stimulated PNMT promoter driven-luciferase activity beyond levels observed with either neurotrophin alone. Finally, post-transcriptional control seems to be another important mechanism by which neurotrophins regulate the adrenergic phenotype. NGF, PACAP, and a combination of the two stimulated both intron-retaining and intronless PNMT mRNA and PNMT protein, but to different extents.
Tai
T C
TC
Laboratory of Molecular and Developmental Neurobiology, Department of Psychiatry, McLean Hospital, Harvard Medical School, 115 Mill St., MRC 116, Belmont, MA 02478, USA.
Wong-Faull
David C
DC
Claycomb
Robert
R
Wong
Dona L
DL
D000311:Adrenal Glands / Q000187:drug effects*; D000818:Animals; D004247:DNA / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D051766:Early Growth Response Protein 1 / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D020932:Nerve Growth Factor / Q000494:pharmacology*; D016716:PC12 Cells; D010625:Phenylethanolamine N-Methyltransferase / Q000235:genetics / Q000378:metabolism; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide / Q000494:pharmacology; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding / Q000187:drug effects; D011493:Protein Kinase C / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects; D016329:Sp1 Transcription Factor / Q000378:metabolism; D013997:Time Factors
D051766:Early Growth Response Protein 1; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D012333:RNA, Messenger; D016329:Sp1 Transcription Factor; D004247:DNA; D020932:Nerve Growth Factor; D010625:Phenylethanolamine N-Methyltransferase; D011493:Protein Kinase C; D048049:Extracellular Signal-Regulated MAP Kinases