title: Role of CCAAT/enhancer-binding protein site in transcription of human neutrophil peptide-1 and -3 defensin genes.
abstract: The human neutrophil defensins (human neutrophil peptides (HNPs)), major components of azurophilic granules, contribute to innate and acquired host immunities through their potent antimicrobial activities and ability to activate T cells. Despite being encoded by nearly identical genes, HNP-1 is more abundant in the granules than HNP-3. We investigated the regulation of HNP-1 and HNP-3 expression at the transcriptional level using a promyelocytic HL-60 cell line. Luciferase analysis showed that transcriptional levels of HNP-1 and HNP-3 promoters were equivalent and that an approximately 200-bp region identical between promoters was sufficient for transcriptional activity. Furthermore, overlapping CCAAT/enhancer-binding protein (C/EBP) and c-Myb sites in the region were found to be required for efficient transcription. Gel mobility shift assay demonstrated that C/EBPalpha predominantly bound to the C/EBP/c-Myb sites using HL-60 nuclear extracts. No specific binding to C/EBP/c-Myb sites was observed in nuclear extracts from mature neutrophils, which expressed neither C/EBPalpha protein nor HNP mRNAs. Taken together, these findings suggest that the difference in the amounts of HNP-1 and HNP-3 peptides in neutrophils is caused by posttranscriptional regulation and that C/EBPalpha plays an important role in the transcription of HNP genes in immature myeloid cells.
authors.affiliation: Department of Biochemistry, Juntendo University, School of Medicine, Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Tsutsumi-Ishii
authors.forename: T
authors.initials: T
authors.lastname: Hasebe
authors.forename: I
authors.initials: I
authors.lastname: Nagaoka
mesh_terms: D020121:5' Untranslated Regions / Q000302:isolation & purification; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics / Q000276:immunology; D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D023082:Defensins; D005786:Gene Expression Regulation / Q000276:immunology; D020570:Genes, myb / Q000276:immunology; D018922:HL-60 Cells; D006367:HeLa Cells; D006801:Humans; D019169:Jurkat Cells; D008969:Molecular Sequence Data; D009504:Neutrophils / Q000276:immunology / Q000378:metabolism*; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000276:immunology; D011506:Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000235:genetics; D050783:Proto-Oncogene Proteins c-ets; D020598:Proto-Oncogene Proteins c-myb / Q000096:biosynthesis; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics; D014158:Transcription, Genetic / Q000276:immunology*; D023084:alpha-Defensins
chemical_list: D020121:5' Untranslated Regions; D022762:CCAAT-Enhancer-Binding Proteins; D004268:DNA-Binding Proteins; D023082:Defensins; D009687:Nuclear Proteins; D011506:Proteins; D011518:Proto-Oncogene Proteins; D050783:Proto-Oncogene Proteins c-ets; D020598:Proto-Oncogene Proteins c-myb; D014157:Transcription Factors; D023084:alpha-Defensins; C406413:human neutrophil peptide 1; C406427:human neutrophil peptide 3