The present studies compared the effects of acute and chronic administration of haloperidol or clozapine on c-fos mRNA expression in the rat medial prefrontal cortex. Acute administration of clozapine, but not haloperidol robustly increased c-fos mRNA expression in the infralimbic and prelimbic cortex of the rat. Even though most c-fos mRNA-expressing neurons in the clozapine- treated animals w...

The c-fos gene encodes a basic region-leucine zipper transcription factor that requires heterodimerization with a member of the Jun family for stable DNA binding. Fos/Jun heterodimers are present in the AP-1 transcription factor complex and both c-Fos and c-Jun are capable of transforming cells (1). Continuous expression of c-fos can lead to aberrant differentiation (2) but may also sometimes b...

Expression of the immediate-early gene c-fos has been advanced as a marker of neuronal activity in the adult nervous system. We sought to test the validity of c-fos mRNA expression as a marker of neuronal activity during seizures and to elucidate specific neurotransmitter receptors whose activation was necessary for seizure-evoked c-fos mRNA expression. We correlated c-fos mRNA expression, meas...

We have previously shown that c-Fos activates phospholipid synthesis through a mechanism independent of its genomic AP-1 activity. Herein, using PC12 cells induced to differentiate by nerve growth factor, the genomic effect of c-Fos in initiating neurite outgrowth is shown as distinct from its nongenomic effect of activating phospholipid synthesis and sustaining neurite elongation. Blocking c-F...

Lysophosphatidic acid (LPA) is a lipid growth factor that exerts diverse biological effects through its cognate receptor-mediated signaling cascades. Recently, we reported that LPA stimulates cAMP response element-binding protein (CREB) through mitogen- and stress-activated protein kinase-1 (MSK1). Previously, LPA has been shown to stimulate c-fos mRNA expression in Rat-2 fibroblast cells via a...

The c-fos protein belongs to a family of transcriptional cofactors that can complex with proteins of the Jun family and activate mRNA transcription from gene promoters containing an activator protein 1 (AP-1) binding element. The shear stress inducibility of the c-fos protein was studied in human and animal cell lines of vastly different origins. Primary human umbilical vein endothelial cells (...

Platelet-derived growth factor (PDGF), the calcium ionophore A23187, and the tumor promoter phorbol myristate acetate stimulated c-fos mRNA levels in control NIH 3T3 cells. However, NIH 3T3 cells transformed by EJ-ras DNA transfection, which have diminished PDGF-stimulated phospholipase C activity, showed a 95% reduction in PDGF-stimulated c-fos mRNA levels. The responses to A23187 and phorbol ...

The expression of the c-fos protooncogene was investigated by in situ hybridization in normal murine bone marrow cells. A strong signal was found in murine marrow cells having the morphologic features of erythroblasts. This result was confirmed in human marrow cells using a double labeling technique (in situ hybridization and immunocytochemistry). A majority (70%) of the cells expressing c-fos ...

Structure-function analysis as well as studies with knock-out and transgenic mice have assigned distinct functions to c-Fos and Fra-1, two components of the transcription factor AP-1 (activator protein-1). To test whether Fra-1 could substitute for c-Fos, we generated knock-in mice that express Fra-1 in place of c-Fos. Fra-1 rescues c-Fos-dependent functions such as bone development and light-i...

The promoter region of the c-fos gene contains several upstream enhancer elements which dictate the transcriptional response to specific intracellular signals. Among these is the cyclic AMP (cAMP)-responsive element, which is required for c-fos expression by cAMP in vitro. However, we have previously shown that cAMP-elevating agents cause only a slight increase in c-fos mRNA levels in intact Sw...