Synergistic activation of the human adrenomedullin gene promoter by Sp1 and AP-2alpha.
Adrenomedullin (AM) is a potent vasodilator peptide, which is ubiquitously expressed and has various biological actions, such as proliferative action and anti-oxidative stress action. AM expression is induced by various stresses, such as hypoxia and inflammatory cytokines, and during cell differentiation. The human AM gene promoter region (-70/-29) contains binding sites for stimulatory protein 1 (Sp1) and activator protein-2alpha (AP-2alpha), and has been shown to be important for the AM gene expression during cell differentiation to macrophages or adipocytes. We here show that Sp1 and AP-2alpha synergistically activate the AM gene promoter. Co-transfection of the reporter plasmid containing the AM promoter region (-103/-29) with Sp1 and AP-2alpha expression plasmids showed that Sp1 and AP-2alpha synergistically increased the promoter activity in HeLa cells. Sp1 or AP-2alpha alone caused only small increases in the promoter activity. EMSA showed that Sp1 bound to the promoter region (-70/-29), whereas AP-2alpha bound to a more upstream promoter region (-103/-71). Thus, the synergistic activation of the human AM gene promoter by Sp1 and AP-2alpha may be mediated by the binding of Sp1 to the promoter region (-70/-29) and the interaction with AP-2alpha, which binds to the promoter region (-103/-71).
Zhang
Yan
Y
Department of Molecular Biology and Applied Physiology, Tohoku University School of Medicine, Sendai, Miyagi, Japan.
Li
Yin
Y
Shibahara
Shigeki
S
Takahashi
Kazuhiro
K
D053607:Adrenomedullin / Q000235:genetics*; D001665:Binding Sites / Q000235:genetics; D024202:Electrophoretic Mobility Shift Assay; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011485:Protein Binding; D016329:Sp1 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D050656:Transcription Factor AP-2 / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
D016329:Sp1 Transcription Factor; D050656:Transcription Factor AP-2; D053607:Adrenomedullin