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  • Cloning and characterizatio...
    Shiomi, Nobuyuki; Myokai, Fumio; Naruishi, Koji; Oyaizu, Kosuke; Senoo, Kyoko; Yamaguchi, Tomoko; Amar, Salomon; Takashiba, Shogo

    FEMS immunology and medical microbiology, 08/2006, Letnik: 47, Številka: 3
    Journal Article

    Abstract We have recently identified lipopolysaccharide tumor-induced tumor necrosis factor α factor (LITAF) as a novel transcription factor controlling necrosis factor (TNF)-α expression in the human monocytic cell line, THP-1. To characterize the human (h) LITAF promoter, we isolated a 1.2-kb DNA fragment and followed this by a screening of human genomic DNA with a hLITAF cDNA probe. A 34-bp sequence domain located from nucleotides −74 to −43 in the hLITAF promoter exhibited the highest basal reporter gene activity; however, the activity was not elevated by lipopolysaccharide (LPS) stimulation. The sequence domain included a consensus sequence for hepatocyte nuclear factor (HNF)-3α, regulating the transcription of many kinds of genes. Interestingly, the DNA sequence position between −542 and −538 in the hLITAF promoter contained the CTCCC motif, which has been reported to act as a specific binding site for hLITAF protein. Electrophoretic mobility shift assays demonstrated that LPS induced the binding of THP-1 nuclear factors to a 22 bp probe containing the CTCCC motif. In addition, hLITAF mRNA and nuclear hLITAF protein increased significantly in the THP-1 cells immediately after LPS stimulation. These results suggest that the consensus sequence for HNF-3α, or a nuclear binding protein to the CTCCC motif, may play an important role in regulating LPS-dependent LITAF transcription.