TY - JOUR
T1 - β-Adrenergic stimulation of cFOS via protein kinase A is mediated by cAMP regulatory element binding protein (CREB)-dependent and tissue-specific CREB- independent mechanisms in corticotrope cells
AU - Boutillier, A. L.
AU - Barthel, F.
AU - Roberts, J. L.
AU - Loeffler, J. P.
PY - 1992
Y1 - 1992
N2 - Catecholamines stimulate proopiomelanocortin (POMC) gene expression in corticotrope cells, but the molecular mechanisms of these effects are not known. While β-adrenergic receptors stimulate the protein kinase A (PKA) system, the POMC promoter does not have classical cAMP-response elements (CREs). Therefore, we investigated the induction of the c-fos protooncogene, previously shown to increase POMC transcription in AtT20 cells. In this corticotrope-derived cell line, we show that activation of β-receptors with isoprenalin (Iso) induces a transient rise in c-fos mRNA levels. Gel mobility shift assays with a labeled AP1 consensus sequence (TGACTCA) showed induction of specific binding activity after Iso treatment. Cotransfection experiments with dominant inhibitory PKA mutants and reporter genes containing c-fos promoter sequences showed that c-fos induction by Iso is entirely dependent on a functional PKA activity. Furthermore, we show that β-receptor induction of c-fos in corticotrophs is mediated by at least two distinct cAMP- responsive sequences. cAMP regulatory element binding (CREB)-dependent induction is observed on the CRE located at -60 bp on the c-fos promoter. A region located in the vicinity of the dyad symetry element (-290) is also found to mediate tissue-specific cAMP induction. Transcriptional activation by this site, although sensitive to PKA antagonism, is not blocked by CREB mutants.
AB - Catecholamines stimulate proopiomelanocortin (POMC) gene expression in corticotrope cells, but the molecular mechanisms of these effects are not known. While β-adrenergic receptors stimulate the protein kinase A (PKA) system, the POMC promoter does not have classical cAMP-response elements (CREs). Therefore, we investigated the induction of the c-fos protooncogene, previously shown to increase POMC transcription in AtT20 cells. In this corticotrope-derived cell line, we show that activation of β-receptors with isoprenalin (Iso) induces a transient rise in c-fos mRNA levels. Gel mobility shift assays with a labeled AP1 consensus sequence (TGACTCA) showed induction of specific binding activity after Iso treatment. Cotransfection experiments with dominant inhibitory PKA mutants and reporter genes containing c-fos promoter sequences showed that c-fos induction by Iso is entirely dependent on a functional PKA activity. Furthermore, we show that β-receptor induction of c-fos in corticotrophs is mediated by at least two distinct cAMP- responsive sequences. cAMP regulatory element binding (CREB)-dependent induction is observed on the CRE located at -60 bp on the c-fos promoter. A region located in the vicinity of the dyad symetry element (-290) is also found to mediate tissue-specific cAMP induction. Transcriptional activation by this site, although sensitive to PKA antagonism, is not blocked by CREB mutants.
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M3 - Article
C2 - 1331087
AN - SCOPUS:0027076014
VL - 267
SP - 23520
EP - 23526
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 33
ER -