title: Down-regulation of human NDR gene in megakaryocytic differentiation of erythroleukemia K562 cells.
abstract: To study the control of hematopoietic cell differentiation, a human negative differentiation regulator (NDR) gene was identified by the comparative analysis of differentially expressed genes in hemato-lymphoid tissues. NDR is expressed preferentially in the adult bone marrow, fetal liver and testis. Immunocytochemistry with anti-NDR antiserum showed the presence of NDR in human erythroleukemia K562 cell line and CD34+ cells sorted from the umbilical cord blood. When fused to the green fluorescent protein (GFP), NDR was directed to the nucleus of mouse 3T3 and K562 cells. Fusion protein with a deletion from residues 7 to 87 was detected in the cytoplasm. NDR appeared not to affect the proliferation of K562 cells when overly expressed. However, its expression was down-regulated during megakaryocytic differentiation of K562 cells induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). Down-regulation of NDR correlated well with up-regulation of megakaryocytic markers, CD41 and CD61. Overexpression of the nuclear NDR-GFP in K562 cells inhibited the expression of CD41 and CD61 in megakaryocytic differentiation. Treatment of K562 cells with GF-109203X (GFX), an antagonist of the protein kinase C (PKC), blocked NDR down-regulation, up-regulated expression of CD41/CD61 and TPA-induced megakaryocytic differentiation. These results suggest a novel function of nuclear NDR protein in regulating hematopoietic cell development.
authors.affiliation: Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan, ROC.
authors.forename: Cheng-Chung
authors.initials: CC
authors.lastname: Liu
authors.forename: Yu-Ling
authors.initials: YL
authors.lastname: Chou
authors.forename: Lan-Yang
authors.initials: LY
authors.lastname: Ch'ang
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence; D000818:Animals; D018952:Antigens, CD34 / Q000378:metabolism; D015415:Biomarkers; D002454:Cell Differentiation / Q000502:physiology*; D015536:Down-Regulation; D005312:Fetal Blood / Q000166:cytology; D020869:Gene Expression Profiling; D015973:Gene Expression Regulation, Leukemic; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D039661:Integrin beta3 / Q000378:metabolism; D020014:K562 Cells; D004915:Leukemia, Erythroblastic, Acute; D008533:Megakaryocytes / Q000166:cytology / Q000502:physiology*; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D040201:Platelet Membrane Glycoprotein IIb / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014018:Tissue Distribution
chemical_list: D018952:Antigens, CD34; D015415:Biomarkers; C435745:HEMGN protein, human; D039661:Integrin beta3; D009687:Nuclear Proteins; D040201:Platelet Membrane Glycoprotein IIb; D011993:Recombinant Fusion Proteins; D013755:Tetradecanoylphorbol Acetate