Characteristics of c-fos and jun B gene expression in A5 cells after beta-adrenoreceptor stimulation and during the cell cycle.
The beta-adrenoreceptor agonist isoproterenol elevates cAMP concentrations in the A5 rat salivary epithelial cell line and rapidly and transiently induces the expression of c-fos and jun B at 30 and 60 min following continuous stimulation of these cells. The induction of both genes is mediated by cAMP. We show here that the inducibility of these genes by isoproterenol or 8-BrcAMP is transcriptionally regulated and short (5 min) incubations of A5 cells with either agent is sufficient to trigger the induction of c-fos and jun B. We also have investigated the expression and inducibility of these genes during the A5 cell cycle. Both c-fos and jun B mRNA are elevated at the early phase of the cell cycle and are detectable throughout the cycle. At different stages of the cell cycle in synchronous A5 cells, both genes are as highly induced by isoproterenol or 8-BrcAMP as in asynchronous A5 cells. These studies provide the first evidence for the transcriptional regulation of c-fos and jun B by beta-adrenergic receptor stimulation or cAMP in an epithelial cell line (A5) and demonstrate the coordinate expression and inducibility of these genes at the different stages of the A5 cell cycle.
Clinical Investigations and Patient Care Branch, National Institute of Dental Research, National Institutes of Health, Bethesda, MD 20892.
C K
CK
Yeh
M A
MA
Chinchetru
E
E
Kousvelari
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000818:Animals; D002453:Cell Cycle / Q000187:drug effects; D002460:Cell Line / Q000187:drug effects; D004268:DNA-Binding Proteins; D015870:Gene Expression / Q000187:drug effects*; D016762:Genes, fos; D016758:Genes, jun; D007150:Immunohistochemistry; D007545:Isoproterenol / Q000494:pharmacology; D016755:Proto-Oncogene Proteins c-jun / Q000032:analysis; D051381:Rats; D014158:Transcription, Genetic
D000318:Adrenergic beta-Agonists; D004268:DNA-Binding Proteins; D016755:Proto-Oncogene Proteins c-jun; D007545:Isoproterenol