5-Hydroxytryptamine induces TIS8/egr-1 and c-fos expression in PC12 cells. Involvement of tyrosine protein phosphorylation.
The TIS8/egr-1 gene is a member of the class of immediate early genes. Originally discovered as a mitogen-induced gene, it can also be induced by synaptic activity. We report here the induction of the TIS8/egr-1 gene by the neurotransmitter 5-hydroxytryptamine (5-HT) in cultured rat phaeochromocytoma PC12 cells. Induction was maximal 40 min after addition of 5-HT to the cells, and declined very rapidly to reach the basal level after 90 min. The electrophoretic mobility-shift assay showed that induction of the TIS8/egr-1 gene by 5-HT was accompained by increased Egr-1 protein binding to its DNA consensus sequence. We found an overall correlation of 5-HT-induced egr-1 expression with that of c-fos expression. The kinetics of the ability of both gene products to bind to their respective DNA consensus sequence was also similar. The 5-HT-induced activation in Egr-1 binding was inhibited by ketanserin and mesulergine, indicating that 5-HT exerted its action via a 5-HT2 receptor subtype. The tyrosine protein kinase inhibitor genistein abolished induction of the TIS8/egr-1 gene, suggesting that tyrosine kinase activity is required for the induction of early genes by 5-HT. Genistein also inhibited 5-HT-induced Egr-1 binding activity. The increase in phosphotyrosine content of focal adhesion kinase we noticed upon addition of 5-HT to cells suggests that this cytoplasmic tyrosine protein kinase mediates the effect of 5-HT in eliciting early gene induction.
Humblot
N
N
INSERM U338, Centre de Neurochimie, Strasbourg, France.
Esteve
L
L
Burgun
C
C
Aunis
D
D
Zwiller
J
J
D000818:Animals; D015152:Blotting, Northern; D002467:Cell Nucleus / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000378:metabolism; D051766:Early Growth Response Protein 1; D004591:Electrophoresis, Polyacrylamide Gel; D017781:Genes, Immediate-Early / Q000187:drug effects / Q000235:genetics*; D017874:Immediate-Early Proteins; D016716:PC12 Cells; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism*; D011233:Precipitin Tests; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis* / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis / Q000302:isolation & purification; D051381:Rats; D011985:Receptors, Serotonin / Q000187:drug effects / Q000502:physiology; D012701:Serotonin / Q000494:pharmacology*; D014157:Transcription Factors / Q000096:biosynthesis* / Q000378:metabolism
D004268:DNA-Binding Proteins; D051766:Early Growth Response Protein 1; C486110:Egr1 protein, rat; D017874:Immediate-Early Proteins; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D011985:Receptors, Serotonin; D014157:Transcription Factors; D019000:Phosphotyrosine; D012701:Serotonin; D011505:Protein-Tyrosine Kinases