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A NF‐κB p65 subunit is indispensable for activating manganese superoxide: Dismutase gene transcription mediated by tumor necrosis factor‐α
Author(s) -
Maehara Kayoko,
Hasegawa Tadao,
Isobe Kenichi
Publication year - 2000
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/(sici)1097-4644(20000601)77:3<474::aid-jcb12>3.0.co;2-h
Subject(s) - microbiology and biotechnology , enhancer , transcription factor , promoter , protein subunit , electrophoretic mobility shift assay , biology , gene expression , reporter gene , transcription (linguistics) , tumor necrosis factor alpha , gene , superoxide dismutase , chemistry , binding site , biochemistry , enzyme , immunology , linguistics , philosophy
Expression of the manganese superoxide dismutase (Mn‐SOD) is induced by tumor necrosis factor‐α (TNF‐α), interleukin‐1 (IL‐1), and lipopolysaccharide (LPS). Recently, a TNF‐responsive element (TNFRE) was identified within the second intron of the murine Mn‐SOD gene. The 5′ CCAAT/enhancer binding protein (C/EBP)‐related region within the TNFRE was responsive to TNF, whereas the 3′ NF‐κB‐related region alone was not. This report describes the minimal promoter region of the Mn‐SOD gene and investigates the cis ‐acting elements and trans ‐acting factors responsible for TNF‐α‐induced Mn‐SOD gene expression. Reporter plasmid transfection studies demonstrated that inducible transcription factors enhanced the transcriptional activity of the Mn‐SOD gene through the intronic enhancer region. Electrophoretic mobility shift assays demonstrated that after TNF‐α stimulation, p50 and p65 NF‐κB subunits bound specifically to the newly identified NF‐κB transcription factor‐binding site, distinct from the previously described NF‐κB site, within the intronic enhancer region. In addition, site‐directed mutagenesis and cotransfection studies demonstrated that the NF‐κB p65 subunit enhanced the transcriptional activity of the Mn‐SOD gene through the newly identified NF‐κB site. These results show that a NF‐κB p65 subunit is mainly involved in the molecular mechanisms controlling TNF‐α‐mediated Mn‐SOD gene transcription. J. Cell. Biochem. 77:474–486, 2000. © 2000 Wiley‐Liss, Inc.