Nuclear factor Y activates the human xanthine oxidoreductase gene promoter

To study the regulation of the human xanthine oxidoreductase (XOR) gene, we cloned 1.9 kb of the promoter region. In reporter gene assays, a construct encompassing nucleotides between -142 to +42 conferred maximal basal activ ity of the XOR promoter in 293T cells, in comparison with shorter (-92 to 42) or longer (up to -1937 to +42) constructs. The promoter activity was lo w in NIH-3T3 cells. The most active construct contained a putative CCAAT mo tif at -119 to -123, Electrophoretic mobility shift assays showed that this sequence hinds the ubiquitous nuclear factor Y (NF-Y), Mutation of the CCA AT motif (CTGAT) abolished the NF-Y binding and considerably reduced the pr omoter activity. Our data suggest an important functional role for NF-Y in the transcriptional activation of the human XOR gene. (C) 2000 Federation o f European Biochemical Societies. Published by Elsevier Science B,V, All ri ghts reserved.