TPA-activated transcription of the human MnSOD gene: Role of transcription factors SP-1 and Egr-1

Sureerut Porntadavity, Yong Xu, Kelley Kiningham, Vivek M. Rangnekar, Daret K. St. Clair, Vivek M. Rangnekar, Sureerut Porntadavity, Virapong Prachayasitikul

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

Abstract

Induction of manganese superoxide dismutase (MnSOD) in response to oxidative stress has been well established in animals, tissues, and cell culture. However, the role of the human MnSOD (hMnSOD) promoter in stimulus-dependent activation of transcription is unknown. The hMnSOD promoter lacks both a TATA and a CAAT box but possesses several GC motifs. In a previous study, we showed that the basal promoter contains multiple Sp1 and AP-2 binding sites and that Sp1 is essential for the constitutive expression of the hMnSOD gene. In this study, we identified an Egr-1 binding site in the basal promoter of hMnSOD. We also found that the basal promoter is responsive to 12-O-tetradecanoylphorbol-13-acetate (TPA)-activated hMnSOD transcription in the human hepatocarcinoma cell line HepG2. The contributions of these binding sites and the roles of the transcription factors Egr-1, AP-2, and Sp1 in the activation of hMnSOD transcription by TPA were investigated by site-directed mutation analysis, Western blotting, and overexpression of transcription factors. The results showed that Sp1 plays a positive role for both basal and TPA-activated hMnSOD transcription, whereas overexpression of Egr-1 has a negative role in the basal promoter activity without any effect on TPA-mediated activation of hMnSOD transcription.

Original languageEnglish
Pages (from-to)473-481
Number of pages9
JournalDNA and Cell Biology
Volume20
Issue number8
DOIs
StatePublished - Aug 2001

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Cell Biology

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