Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P05412 (c-Jun)
 11,453 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The recent finding that neurotransmitters and drugs that affect neurotransmission have important influences on gene expression suggests that drug-induced alterations in gene expression may underlie many long-term effects of addictive drugs, for example, dependence and drug-seeking behaviors. These long-term adaptive responses to opiate drugs have been particularly difficult to understand at a mechanistic level. Data presented here indicate that the gene encoding the opioid precursor proenkephalin is highly regulated by neural activity, second-messenger pathways, and PKA. These observations raise the possibility that drugs of abuse (e.g., opiates acting through opiate receptors) may act at the genetic level to modulate the expression of endogenous opiates and that these effects may underlie one component of the brain's long-term adaptive response to exogenous opiates. The transgenic animals described above can be used to investigate opiate drug-induced changes in proenkephalin gene expression, allowing rapid analysis of changes in proenkephalin gene expression in highly restricted populations of neurons in a fashion previously impossible. In addition, by analyzing the effects of specific enhancer mutations on tissue-specific and transsynaptic regulation of proenkephalin expression, transgenic models will permit mechanistic investigations within the intact nervous system that cannot otherwise be undertaken. Investigation of mechanisms underlying this process requires the analysis of intracellular signaling pathways, responsive DNA regulatory elements, and the transcription factors transducing synaptic signals into gene regulation. In the studies described herein, we demonstrate that AP-1 complexes consisting of different Jun proteins differentially regulate proenkephalin transcription at the CRE-2 element. c-Jun constitutively activates proenkephalin transcription, whereas JunD activates in a fashion completely dependent on the activation of second-messenger pathways and the cAMP-dependent PKA. JunB alone has no effect on proenkephalin gene expression, yet this molecule effectively blocks activation mediated by JunD and, hence, may act as a repressor. These data are consistent with a model (figure 4) in which preexisting JunD mediates the rapid cAMP-dependent activation of the proenkephalin enhancer, whereas IEGs such as JunB or c-Fos mediate the protein synthesis-dependent inactivation. Because c-Jun activates proenkephalin transcription constitutively, induction of c-Jun may lead to a further and prolonged activation of proenkephalin gene expression. Hence, the ratio of c-Jun to JunB induction may determine whether proenkephalin is repressed or further activated.
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PMID:Regulation of opioid gene expression: a model to understand neural plasticity. 149 20

Phorbol ester tumor promoters activate gene transcription by regulating both the synthesis and posttranslational modification of the activator protein 1 (AP-1) transcription factor, c-Jun and JunB are components of the mammalian AP-1 complex. Here we demonstrate that in U-937 human leukemic cells, phorbol esters stimulate the phosphorylation of the amino terminus of human c-Jun (JUN) but not human JunB (JUNB). Mutational analysis indicates that serine-63 and -73, which reside within the putative regulatory domain of JUN, are required for both constitutive and phorbol 12-myristate 13-acetate-inducible N-terminal JUN phosphorylation. To determine the functional role of this N-terminal phosphorylation, we prepared several chimeric proteins containing the N-terminal 84 amino acids (positions 5-89) of human JUN or murine JUNB fused to the yeast GAL4 DNA-binding domain. This region was found to be sufficient for the phorbol ester-inducible transcriptional activity of JUN, but not JUNB. This induction was abolished by the mutation of serine-63 and -73 to leucine residues. Thus, we propose that phorbol esters enhance the trans-activation potential of JUN, but not JUNB, by the phosphorylation of the N-terminal regulatory domain of JUN.
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PMID:Phorbol ester-induced amino-terminal phosphorylation of human JUN but not JUNB regulates transcriptional activation. 149 19

Anergy is a mechanism of T lymphocyte tolerance induced by antigen receptor stimulation in the absence of co-stimulation. Anergic T cells were shown to have a defect in antigen-induced transcription of the interleukin-2 gene. Analysis of the promoter indicated that the transcription factor AP-1 and its corresponding cis element were specifically down-regulated. Exposure of anergic T cells to interleukin-2 restored both antigen responsiveness and activity of the AP-1 element.
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PMID:Transactivation by AP-1 is a molecular target of T cell clonal anergy. 150 65

c-Jun, a major component of the inducible transcription factor AP-1, is a phosphoprotein. In nonstimulated fibroblasts and epithelial cells, c-Jun is phosphorylated on a cluster of two to three sites abutting its DNA-binding domain. Phosphorylation of these sites inhibits DNA binding, and their dephosphorylation correlates with increased AP-1 activity. We show that two of these sites, Thr-231 and Ser-249, are phosphorylated by casein kinase II (CKII). Substitution of the third site, Ser-243, by Phe interferes with phosphorylation of the inhibitory sites in vivo and by purified CKII in vitro. Microinjection into living cells of synthetic peptides that are specific competitive substrates or inhibitors of CKII results in induction of AP-1 activity and c-Jun expression. Microinjection of CKII suppresses induction of AP-1 by either phorbol ester or an inhibitory peptide. These results suggest that one of the roles of CKII, a major nuclear protein kinase with no known functions, is to attenuate AP-1 activity through phosphorylation of c-Jun.
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PMID:Casein kinase II is a negative regulator of c-Jun DNA binding and AP-1 activity. 142 36

A strong enhancer element, GPEI, of the glutathione transferase P gene (GST-P) gene is composed of two phorbol 12-O-tetradecanoate 13-acetate (TPA) responsive element (TRE)-like sequences at opposite orientation. Unlike TRE sequences of other genes, GPEI exhibits a strong enhancer activity in F9 cells, which contains little AP-1. GPEI bound to AP-1 In vitro and GST-P expression was activated by TPA and exogenously introduced c-jun gene in a rat fibroblast cell line. Both the stimulated expression of GST-P gene by TPA and that by over-expressed c-Jun were suppressed to the basal level by dexamethasone, an inhibitor of AP-1. Basal expression of GST-P gene, however, was not inhibited by dexamethasone. Transfected chloramphenicol acetyltransferase (CAT) gene having GPEI also behaved as the endogenous GST-P gene. These results indicate that the GPEI is activated by AP-1 but constitutive activity of this enhancer in a rat fibroblast cell line 3Y1 cells is due to some unknown mechanism other than AP-1.
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PMID:Suppression of glutathione transferase P expression by glucocorticoid. 153 Jun 52

Laminin, a basement membrane glycoprotein, has diverse biological activities including cell adhesion, growth, and differentiation. However, little is known concerning the signal transduction and active site involved in cell growth. In this study, we have shown that laminin and a 19-mer peptide (PA22-2) from the carboxyl-terminal end of the long arm of the laminin A chain, which was previously shown to promote cell adhesion and neurite outgrowth, stimulate thymidine incorporation and cell growth of PC12 cells. Laminin and PA22-2 (PA) were also found to induce a rapid and transient mRNA expression of c-fos and c-jun protooncogenes in PC12 cells. Further, both laminin and PA stimulated the DNA binding activity of c-Fos and c-Jun protein complex to the AP-1 site. We have also found that there is a correlation between cell growth, c-fos expression, and the ability of cell attachment to laminin or to PA in different cell types. These results suggest that the PA sequence is a potent site in laminin for both signal transduction and cell growth.
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PMID:Signaling site of laminin with mitogenic activity. 153 19

In HeLa cells transcription of the c-jun gene is activated strongly and rapidly by ultraviolet (UV) irradiation and, to a somewhat lesser extent, by treatment with phorbol ester tumor promoters. In the same cells UV and phorbol esters only marginally enhance the abundance of RNA transcribed from the jun D gene and from the gene coding for the serum response factor (which in turn acts on the UV and phorbol ester response element of the c-fos gene). In contrast to c-jun, jun B transcription is induced more efficiently by phorbol ester than by UV irradiation, suggesting that the members of the jun family are differently regulated. The promoter of c-jun carries two enhancer elements resembling AP-1 binding sites: the jun1 UV response element (URE-71 TGACATCA -64) and the jun2 URE (-190 TTACCTCA-183). These elements act independently in the UV induced expression of c-jun. In the context of the complete c-jun promoter they seem not to be required for c-jun induction by phorbol esters. When fused to the Herpes simplex thymidine kinase promoter, however, the isolated elements mediate induction by both UV and phorbol esters. UV and phorbol ester treatment of cells increases the binding of transcription factors to both elements. Both elements bind factors different in modification or/and constitution from AP-1, the heterodimeric transcription factor composed of c-Fos and c-Jun that controls the activity of the UV and phorbol ester response element (-72 TGAGTCA-66) of the human collagenase gene.
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PMID:Ultraviolet-radiation induced c-jun gene transcription: two AP-1 like binding sites mediate the response. 156 Dec 39

JunB, a member of the jun gene family of transcription factors, is distinguished from c-Jun by its differential activity on certain arrangements of promoter regulatory elements and the ability of JunB to inhibit the action of cJun in both transforming and trans-activating assays. We have tested the potential negative regulatory role of JunB during the retinoic acid induced differentiation of F9 murine embryonal carcinoma cells. Constitutive expression of high levels of JunB in F9 cells failed to inhibit the differentiation dependent induction of c-Jun or the coincident expression of differentiation markers keratin 8 and 18, tissue plasminogen activator, and laminin B1. Among these marker genes, keratin 18, has been shown to contain an AP-1 binding site, TGA(C/G)TCA, which is essential for high level, differentiation dependent expression and which is transactivated by Jun and Fos proteins. These results suggest that JunB does not play a major negative or positive regulatory role during the retinoic acid induced differentiation of F9 cells.
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PMID:JunB does not inhibit the induction of c-Jun during the retinoic acid induced differentiation of F9 cells. 158 7

Transcription factor c-Jun appears to be a nuclear target of the Ras-induced signal transduction pathway. In fact, some experiments show that transforming forms of the Ras protein cooperate with Jun in transcriptional activation mediated by an AP-1 site and others indicate that the two oncoproteins cooperate in cellular transformation. Although it is likely that intracellular signaling systems activated by Ras might act directly on c-Jun by inducing specific phosphorylation, it is unclear how c-Jun participates in the transformation process. Here, we present results obtained with a LexA-Jun zipper fusion that lacks both the transcriptional activation domains and the basic region of the DNA-binding domain of c-Jun and contains only the intact leucine-zipper domain. This fusion product has a dominant negative effect on the transcriptional activation elicited by phorbol esters, c-Jun, c-Fos, Ras and E1A on an AP-1-responsive site. An analogous LexA-Fos zipper fusion has similar effects on transcriptional induction. The LexA-Jun zipper fusion acts further as a transformation suppressor, since it causes the generation of nontransformed revertants of ras-transformed cells. This effect is likely to be elicited by the dimerization potential of the Jun leucine zipper trapping cellular Jun and/or Fos in a protein complex unable to bind to DNA. These data implicate further that Ras-mediated transformation involves functional transcription factor AP-1 and that it is possible to interfere with cell transformation by interfering simply with the dimerization of transcription factors involved in the transformation process.
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PMID:Transformation and transactivation suppressor activity of the c-Jun leucine zipper fused to a bacterial repressor. 158 58

Polyoma virus middle-sized tumor (PymT) antigen is required for neoplastic cell transformation by polyoma virus. We studied changes in gene expression accompanying expression of PymT in murine fibroblasts. These experiments showed that PymT differentially affects several growth-related genes. c-jun protooncogene expression was highly increased, whereas the expression of two growth arrest-specific genes (gas) was reduced, in cells transformed by PymT. Cotransfection experiments showed that the increase in c-jun expression resulted from elevated activity of the transcription factor AP-1 and was mediated through the phorbol 12-tetradecanoate 13-acetate response element in the c-jun promoter. The degree of c-Jun/AP-1 activation by different PymT mutants correlated with their transforming capability, suggesting that regulation of c-Jun/AP-1 activity may play a role in cell transformation by polyoma virus.
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PMID:Induction of c-jun protooncogene expression and transcription factor AP-1 activity by the polyoma virus middle-sized tumor antigen. 159 1


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