Role for NF-kappa B in the regulation of ferritin H by tumor necrosis factor-alpha.
Ferritin is a ubiquitously distributed iron-binding protein that plays a key role in cellular iron homeostasis. It is composed of two subunits, termed H (heavy or heart) and L (light or liver). In fibroblasts and other cells, the cytokine tumor necrosis factor-alpha (TNF) specifically induces synthesis of the ferritin H subunit. Using nuclear run-off assays, we demonstrate that this TNF-dependent increase in ferritin H is mediated by a selective increase in ferritin H transcription. Transfection of murine fibroblasts with chimeric genes containing the 5'-flanking region of murine ferritin H fused to the human growth hormone reporter gene reveals that the cis-acting element that mediates this response is located approximately 4.8 kilobases distal to the start site of transcription. Deletion analyses delimit the TNF-responsive region to a 40-nucleotide sequence located between nucleotides -4776 and -4736, which we term FER-2. Electrophoretic mobility shift assays and site-specific mutations indicate that this region contains two independent elements: one contains a sequence that binds a member of the NF-kappa B family of transcription factors, and a second contains a novel sequence that partially conforms to the NF-kappa B consensus sequence and may bind a different member of the NF-kappa B/Rel transcription factor family. Thus, effects of an inflammatory cytokine on ferritin are mediated by a family of transcription factors responsive to oxidative stress.
Kwak
E L
EL
Department of Medicine, Stanford University Medical School, California 94305, USA.
Larochelle
D A
DA
Beaumont
C
C
Torti
S V
SV
Torti
F M
FM
D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D017931:DNA Primers; D005293:Ferritins / Q000096:biosynthesis*; D005786:Gene Expression Regulation / Q000187:drug effects*; D013006:Growth Hormone / Q000096:biosynthesis; D006801:Humans; D046911:Macromolecular Substances; D051379:Mice; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D016328:NF-kappa B / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D012260:Ribonucleases; D014158:Transcription, Genetic; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D017931:DNA Primers; D046911:Macromolecular Substances; D016328:NF-kappa B; D011993:Recombinant Fusion Proteins; D014409:Tumor Necrosis Factor-alpha; D013006:Growth Hormone; D005293:Ferritins; D012260:Ribonucleases