title: Early growth-responsive-1-dependent manganese superoxide dismutase gene transcription mediated by platelet-derived growth factor.
abstract: Manganese superoxide dismutase Mn-SOD plays a major role in protecting mitochondria from oxidative damage. Overexpression of Mn-SOD maintains cell survival under conditions that lead to apoptotic death. In addition to the antioxidative enzyme, platelet-derived growth factor (PDGF) is a principal survival factor that inhibits apoptosis and promotes proliferation by activating survival signaling pathways in various cells. Here we show that PDGF induced the expression of the Mn-SOD gene in NIH3T3 cells, and its induction was associated with early growth response-1 (Egr-1), a transcription factor. An electrophoretic mobility shift assay demonstrated that Egr-1 bound to the proximal promoter of the Mn-SOD gene in response to PDGF. The proximal promoter region of Mn-SOD was shown to be transcriptionally responsive to both basal and PDGF stimulation by transfection studies. Forced expression of Egr-1 in the cells activated Mn-SOD transcription in a dose-dependent manner. The pathway by which PDGF induced Egr-1 involved the mitogen-activated protein kinase kinase-1 (MEK1) and extracellular signal-regulated kinases 1 and 2 (ERK1/2), because the effect of PDGF on the induction of Egr-1 was blocked by U0126, a specific MEK1 inhibitor. These findings indicate that the induction of Mn-SOD is part of the anti-apoptotic properties mediated by PDGF.
authors.affiliation: Department of Basic Gerontology, National Institute for Longevity Sciences, 36-3 Gengo, Morioka-cho, Obu, Aichi 474-8522, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Maehara
authors.forename: K
authors.initials: K
authors.lastname: Oh-Hashi
authors.forename: K I
authors.initials: KI
authors.lastname: Isobe
mesh_terms: D016475:3T3 Cells; D000818:Animals; D004247:DNA; D004268:DNA-Binding Proteins / Q000378:metabolism*; D051766:Early Growth Response Protein 1; D015971:Gene Expression Regulation, Enzymologic; D017874:Immediate-Early Proteins; D048369:MAP Kinase Kinase 1; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D010982:Platelet-Derived Growth Factor / Q000378:metabolism* / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid; D015398:Signal Transduction; D016329:Sp1 Transcription Factor / Q000378:metabolism; D013482:Superoxide Dismutase / Q000235:genetics*; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic; D016335:Zinc Fingers
chemical_list: D004268:DNA-Binding Proteins; D051766:Early Growth Response Protein 1; C486109:Egr1 protein, mouse; D017874:Immediate-Early Proteins; D010982:Platelet-Derived Growth Factor; D016329:Sp1 Transcription Factor; D014157:Transcription Factors; D004247:DNA; D013482:Superoxide Dismutase; D017346:Protein Serine-Threonine Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048369:MAP Kinase Kinase 1; C482125:MAP2K1 protein, human; C482127:Map2k1 protein, mouse; D020929:Mitogen-Activated Protein Kinase Kinases