Promoter activity and regulation of the CYP4F2 leukotriene B(4) omega-hydroxylase gene by peroxisomal proliferators and retinoic acid in HepG2 cells.

Promoter activity and regulation of the CYP4F2 leukotriene B(4) omega-hydroxylase gene by peroxisomal proliferators and retinoic acid in HepG2 cells.

Zhang X; Chen L; Hardwick J P

Archives of biochemistry and biophysics

2000

2000-06

The human liver CYP4F2 gene (Accession No. AF221943) encodes a leukotriene B(4) omega-hydroxylase that metabolizes leukotriene B(4) (LTB(4)) to a less potent proinflammatory eicosanoid, 20-OH-LTB(4). We sequenced a 6.7-kb genomic fragment of the human CYP4F2 gene that has the first five exons and 500 bp of the 5'-flanking region. The major transcription start site was found to be 49 bp upstream of the 3' end of exon 1 and the ATG translation initiation codon was located in exon 2. Besides the TATA box at -39 bp and basal transcription factor binding sites, the promoter region and 412-bp intron 1 have several putative binding sites for nuclear factors that may mediate the inflammatory response and lipid homeostasis. We found two DR1 elements in the 5' promoter, a DR2 element in intron 1, and RXR/RAR binding sites in both intron 1 and the 5' promoter. DNase I footprinting revealed three protected sequences, with the region containing two CAATT boxes at -71 and -111 bp important in CYP4F2 gene expression. Luciferase reporter assays showed that the 500-bp upstream sequence has strong promoter activity. Transient transfection experiments identified two sites in the 5' promoter and intron 1 that cooperate in gene transcription while exon 1 and a

*Gene Expression Regulation; *Promoter Regions; Amino Acid Sequence; Base Sequence; Cell Line; Cloning; Cytochrome P-450 CYP4A; Cytochrome P-450 Enzyme System/*genetics/metabolism; Cytochrome P450 Family 4; Cytoplasmic and Nuclear/metabolism; DNA; DNA Footprinting; Enzymologic; Exons; Genes; Genetic; Genetic/drug effects; Humans; Introns; Leukotriene B4/metabolism; Mixed Function Oxygenases/metabolism; Models; Molecular; Molecular Sequence Data; Peroxisome Proliferators/*metabolism; Receptors; Reporter; Retinoic Acid Receptor alpha; Retinoic Acid/metabolism; Sequence Analysis; Transcription; Transcription Factors/metabolism; Transfection; Tretinoin/*metabolism

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