Cytokine-inducible enhancer with promoter activity in both the rat and human manganese-superoxide dismutase genes.
Diverse pro-inflammatory mediators regulate transcription of the gene (MnSOD) encoding the mitochondrial anti-oxidant protein manganese-superoxide dismutase. Understanding the regulation of this gene is crucial to comprehending its role in cytoprotection. In transfected lung epithelial cells, a human-growth-hormone reporter gene system was utilized to identify a potential enhancer in the MnSOD genomic fragment previously shown to contain multiple DNase-I-hypersensitive sites. Northern analysis demonstrated a 10-20-fold increase in response to pro-inflammatory mediators. Inclusion of the MnSOD genomic fragment in reporter constructs was necessary to mimic these stimulus-dependent endogenous levels. The inducible enhancer element was localized to a 260 bp fragment in intron 2, coinciding with a previously defined DNase-I-hypersensitive site. This element functions in an orientation- and position-independent manner as well as with the heterologous thymidine kinase promoter. In addition, we have demonstrated that a homologous sequence within the human MnSOD gene exhibits identical enhancer activity. A novel characteristic of the rat and human enhancer elements involves the ability to promote cytokine-inducible transcription in the absence of a classical promoter.
Rogers
R J
RJ
Department of Biochemistry, University of Florida College of Medicine, Gainesville, FL, USA.
Chesrown
S E
SE
Kuo
S
S
Monnier
J M
JM
Nick
H S
HS
D000818:Animals; D002401:Cathepsin B / Q000235:genetics; D002460:Cell Line; D016207:Cytokines / Q000494:pharmacology*; D004742:Enhancer Elements, Genetic / Q000187:drug effects*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D017930:Genes, Reporter; D019382:Human Growth Hormone / Q000235:genetics; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology; D007438:Introns; D007527:Isoenzymes / Q000235:genetics; D008070:Lipopolysaccharides / Q000494:pharmacology; D008168:Lung; D011401:Promoter Regions, Genetic / Q000187:drug effects*; D051381:Rats; D020545:Respiratory Mucosa; D013482:Superoxide Dismutase / Q000235:genetics*; D014158:Transcription, Genetic / Q000187:drug effects*; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D016207:Cytokines; D007375:Interleukin-1; D007527:Isoenzymes; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D019382:Human Growth Hormone; D013482:Superoxide Dismutase; D002401:Cathepsin B