title: The human CD34 hematopoietic stem cell antigen promoter and a 3' enhancer direct hematopoietic expression in tissue culture.
abstract: The human CD34 hematopoietic stem cell antigen is a highly glycosylated type 1 membrane protein of unknown function. CD34 is expressed on 1% to 4% of bone marrow cells, including pluripotent stem cells and committed progenitors of each hematopoietic lineage. CD34 has also been shown to be expressed on the small vessel endothelium of a variety of tissues and on a subset of bone marrow stromal cells. We have chosen to use the human CD34 gene as model to examine the transcription factors and cis-elements required for stem cell/progenitor cell-specific gene regulation. We show here that the CD34 gene is transcriptionally regulated in tissue culture cells. Using a luciferase reporter gene, we have isolated and characterized an active CD34 promoter. A CD34-luciferase construct, containing 4.5 kb of 5' flanking DNA from a CD34 genomic clone, was 30-fold more active in CD34+ tissue culture cells than in HeLa cells. Sequences from the 3' end of the CD34 gene were shown to have enhancing activity in CD34+ T-lymphoblastic RPMI-8402 cells and not in CD34- U937 cells or in nonhematopoietic HeLa cells. We also show that a cytidine-guanosine island in the 5' end of the CD34 gene is heavily methylated in two CD34- hematopoietic cell lines and demethylated in two CD34+ cell lines. Analysis of the CD34 promoter should result in the identification of stem cell/progenitor cell-specific transcription factors and should provide a means to direct the expression of heterologous genes in hematopoietic stem cells and progenitors.
mesh_terms: D015703:Antigens, CD / Q000235:genetics*; D018952:Antigens, CD34; D001358:Avian Sarcoma Viruses / Q000235:genetics; D001483:Base Sequence; D002460:Cell Line; D002467:Cell Nucleus / Q000502:physiology*; D004273:DNA, Neoplasm / Q000235:genetics; D004742:Enhancer Elements, Genetic; D015972:Gene Expression Regulation, Neoplastic; D006367:HeLa Cells; D006412:Hematopoietic Stem Cells / Q000502:physiology*; D006801:Humans; D007438:Introns; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D010957:Plasmids; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D015183:Restriction Mapping; D017384:Sequence Deletion; D014158:Transcription, Genetic; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D015703:Antigens, CD; D018952:Antigens, CD34; D004273:DNA, Neoplasm; D009838:Oligodeoxyribonucleotides