Transcriptional activation of apurinic/apyrimidinic endonuclease (Ape, Ref-1) by oxidative stress requires CREB.
Apurinic/apyrimidinic endonuclease (APE alias Ref-1) is a multifunctional enzyme involved in DNA repair and redox regulation of transcription factors (e.g., AP-1). It also acts as a repressor of its own and other genes. Recently, it was shown that the level of APE mRNA and protein is enhanced upon treatment of cells with oxidative agents, such as hydrogen peroxide (H(2)O(2)), which gives rise to an adaptive response of cells to oxidative stress. Induction of APE is due to APE promoter activation. To elucidate the mechanism of transcriptional activation of APE by oxidative agents, we introduced mutations into the cloned human APE promoter and checked its activity in transient transfection assays. Here we demonstrate that mutational inactivation of a CREB binding site (CRE) present within the promoter completely abolished APE promoter activation by H(2)O(2), indicating that CREB is required for APE induction. The CRE element in the context of the APE promoter sequence binds c-Jun and ATF-2, which was shown in gel retardation experiments. Under conditions of induction of APE by H(2)O(2), the expression of c-Jun was significantly enhanced, which supports the view that induction of c-Jun is involved in signaling leading to APE promoter activation by oxidative stress.
Grösch
S
S
Institute of Toxicology, University of Mainz, Obere Zahlbacher Strasse 67, Mainz, D-55131, Germany.
Kaina
B
B
D051698:Activating Transcription Factor 2; D000818:Animals; D001665:Binding Sites; D016466:CHO Cells; D019757:Carbon-Oxygen Lyases / Q000235:genetics*; D006224:Cricetinae; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism / Q000502:physiology*; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D016297:Mutagenesis, Site-Directed; D016877:Oxidants / Q000494:pharmacology; D018384:Oxidative Stress; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic; D014162:Transfection
C497105:ATF2 protein, human; D051698:Activating Transcription Factor 2; D017362:Cyclic AMP Response Element-Binding Protein; D016877:Oxidants; D016755:Proto-Oncogene Proteins c-jun; D014157:Transcription Factors; D006861:Hydrogen Peroxide; D019757:Carbon-Oxygen Lyases; C085108:APEX1 protein, human; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase