共查询到20条相似文献,搜索用时 578 毫秒
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M Sakai M Muramatsu S Nishi 《Biochemical and biophysical research communications》1992,187(2):976-983
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. 相似文献
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Cell-extracellular matrix interactions stimulate the AP-1 transcription factor in an integrin-linked kinase- and glycogen synthase kinase 3-dependent manner. 总被引:8,自引:0,他引:8 下载免费PDF全文
Armelle A. Troussard Clara Tan T. Nathan Yoganathan Shoukat Dedhar 《Molecular and cellular biology》1999,19(11):7420-7427
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Laderoute KR Mendonca HL Calaoagan JM Knapp AM Giaccia AJ Stork PJ 《The Journal of biological chemistry》1999,274(18):12890-12897
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To investigate further the molecular mechanisms of progestin regulation of human breast cancer cell growth, we studied the effect of progestins on expression of the protooncogene c-jun and other members of the jun family, jun-B and jun-D, in T-47D human breast cancer cells. The progestin medroxyprogesterone acetate (MPA) increased c-jun mRNA levels in a time- and dose-dependent fashion. Maximal effects were seen after 3 h of treatment with 10-100 nM MPA. Under these conditions, the c-jun mRNA was increased 5.4-fold above the control level. Although the c-jun mRNA level was increased by cycloheximide alone, a further 2.4-fold increase was seen when the cells were treated with MPA in the presence of cycloheximide. The p39 c-jun protein was also increased 3.8-fold by this treatment. Maximum levels of p39 c-jun protein were achieved 9 h after treatment, and this level was maintained for at least 24 h. Dexamethasone and dihydrotestosterone did not increase the p39 c-jun protein level under these conditions. However, MPA treatment of T-47D cells resulted in a 55% decrease in overall AP-1 activity, as measured by transient transfection of an AP-1-regulated chloramphenicol acetyltransferase reporter gene. These effects were all reversible by cotreatment with a 10-fold higher concentration of the antiprogestin RU 486. MPA decreased jun-B mRNA levels 50% 1 h after treatment in T-47D cells.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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