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 effect of transient transfection with expression vector of c-Fos on the expression of 12-lipoxygenase in human epidermoid carcinoma A431 cells was studied. Overexpression of c-Fos increased the expression of 12-lipoxygenase mRNA and enzyme activity, and also activated the promoter activity of 12-lipoxygenase gene in a dose-dependent manner. Co-transfection with c-Fos and c-Jun expression vectors in cells synergistically increased the promoter activity of 12-lipoxygenase. With the aid of additional 5'-deletion and site-directed mutagenesis, the downstream and middle Sp1 sites residing at -123 to -114 bp and -158 to -150 bp were found to be critical for the c-Fos response of activating the transcription of human 12-lipoxygenase gene. Furthermore, the specific role of Sp1 in c-Fos response was confirmed by using the reporter plasmid driven by SV40 early promoter. These results indicate that the requirement of Sp1-binding sites in the promoter region of 12-lipoxygenase gene for c-Fos response is similar to that previously observed in EGF response.
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PMID:Overexpression of c-Fos enhances the transcription of human arachidonate 12-lipoxygenase in A431 cells. 1044 14

The role of mitogen-activated protein kinase signaling and the transcription factor c-Jun in epidermal growth factor (EGF)-induced expression of 12-lipoxygenase in human epidermoid carcinoma A431 cells was studied. EGF increased the activation of extracellular signal-regulated kinase (ERK) and c-Jun amino terminal kinase (JNK) in a time-dependent manner. Treatment of the cells with an mitogen-activated protein kinase kinase inhibitor, PD098059 (30 microM), inhibited the EGF- and pSV2ras-induced expression of 12-lipoxygenase mRNA. Transfection of the cells with Ras, ERK2, Rac, JNK dominant negative mutants pMMrasDN, K52R ERK2, RacN17, and mJNK all inhibited the EGF-induced promoter activation of the 12-lipoxygenase gene. EGF induced the expression of c-Jun and the activity of transcription factor activator protein 1 in cells, and these effects were blocked by the treatment with K52R ERK2 and mJNK. Overexpression of c-Jun increased the expression of 12-lipoxygenase mRNA and enzyme activity. Furthermore, the Sp1-binding sites in the promoter region of the 12-lipoxygenase gene were requisite for c-Jun response, which was similar to that previously observed in EGF response. The results indicate that the EGF-induced expression of 12-lipoxygenase in A431 cells was mediated through the Ras-ERK and Ras-Rac-JNK signal pathways. Subsequent induction of c-Jun led by ERK and JNK activation was essential for this EGF response.
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PMID:Essential role of mitogen-activated protein kinase pathway and c-Jun induction in epidermal growth factor-induced gene expression of human 12-lipoxygenase. 1061 90

Evidence suggests that leukocyte type 12-lipoxygenase (12-LO) plays an important role in cell growth. However, the role of 12-LO in cardiac cell growth has not been tested. We have now stably overexpressed 12-LO cDNA in rat fetal cardiac fibroblasts to evaluate the role of the 12-LO pathway in cardiac cell growth. Overexpression of 12-LO increased cell [(3)H]leucine incorporation by 2.1+/-0.1-fold (P<0.01) and cell protein content by 2.2+/-0. 3-fold (P<0.01) over mock-transfected cells. These findings were confirmed in additional clones. Baicalein, a 12-LO enzyme inhibitor, dose-dependently inhibited serum-induced leucine incorporation in cardiac fibroblast cells as well as partially inhibited leucine incorporation in cells overexpressing 12-LO. 12-LO overexpression also caused cell [(3)H]thymidine incorporation to increase by 3.4+/-0.3-fold (P<0.01). Cell flow cytometry analysis showed that the size of 12-LO-overexpressing cells was markedly enlarged compared with that of mock-transfected cells. The fibronectin content of the 12-LO-overexpressing cardiac fibroblasts was also significantly increased. We next evaluated the effects of 12-LO RNA overexpression on kinase pathways linked to cellular growth. The overexpression of 12-LO enhanced extracellular signal-regulated kinase activity (4. 1+/-0.5-fold), c-Jun NH(2)-terminal kinase activity (2.9+/-0.5-fold), and p38 mitogen-activated protein kinase activity (2.2+/-0.3-fold). Pretreatment with SB202190 (100 nmol/L), a specific inhibitor of p38, prevented the increases in protein content of 12-LO-overexpressing cardiac fibroblast cells. These data clearly demonstrate that the overexpression of 12-LO causes cell growth of cardiac fibroblasts, thus supporting the role of 12-LO as a novel growth-promoting pathway in the heart.
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PMID:Overexpression of 12-lipoxygenase causes cardiac fibroblast cell growth. 1113 76