title: Forced GATA-1 expression in the murine myeloid cell line M1: induction of c-Mpl expression and megakaryocytic/erythroid differentiation.
abstract: The "zinc-finger" transcription factor GATA-1 was first shown in cells of erythroid lineage. It is also expressed in cells of other hematopoietic lineages including megakaryocytes, mast cells, and eosinophils. GATA-1 is now considered to be one of the central regulators in hematopoietic cell differentiation. To further analyze the role of GATA-1 in controlling differentiation from hematopoietic stem cells, we investigated the phenotypic changes induced by the overexpression of murine GATA-1 in the murine myeloid leukemic cell line, M1. Forced expression of GATA-1 induced the appearance of erythroid cells and megakaryocytes as assessed by cellular morphology, acetylcholinesterase activity, and expression of platelet factor 4 and beta-globin mRNA synthesis. Because the c-mpl ligand, thrombopoietin, plays an important role in megakaryopoiesis, the expression of c-mpl and c-mpl ligand (thrombopoietin) mRNA was analyzed by Northern blot and reverse transcription-polymerase chain reaction (RT-PCR) in M1 cells overexpressing GATA-1. The c-mpl ligand mRNA was equally expressed both in parental M1 cells and in those transfected with the GATA-1 expression vector. In contrast, the mRNA expression of c-mpl was increased only in GATA-1 expressing M1 cells differentiated towards erythroid and megakaryocyte lineages. The increased expression of c-mpl mRNA induced by GATA-1 raised the question as to whether or not GATA-1 transactivated the c-mpl promoter. The activity of the c-mpl promoter in the presence of cotransfected GATA-1 was significantly increased compared with that of the control. A plasmid with the mutated GATA-binding site did not show transactivation ability in the cotransfection with a GATA expression vector. These findings suggest that the upregulation of c-mpl induced by GATA-1 expression in M1 cells is closely associated with erythroid and megakaryocytic differentiation.
authors.affiliation: Department of Cell Differentiation, Kumamoto University School of Medicine, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Yamaguchi
authors.forename: L I
authors.initials: LI
authors.lastname: Zon
authors.forename: S J
authors.initials: SJ
authors.lastname: Ackerman
authors.forename: M
authors.initials: M
authors.lastname: Yamamoto
authors.forename: T
authors.initials: T
authors.lastname: Suda
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004912:Erythrocytes / Q000166:cytology* / Q000378:metabolism; D050981:Erythroid-Specific DNA-Binding Factors; D050982:GATA1 Transcription Factor; D005786:Gene Expression Regulation; D006410:Hematopoiesis / Q000235:genetics; D008533:Megakaryocytes / Q000166:cytology* / Q000378:metabolism; D051379:Mice; D009363:Neoplasm Proteins; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D018121:Receptors, Cytokine; D053628:Receptors, Thrombopoietin; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D050982:GATA1 Transcription Factor; C494689:Gata1 protein, mouse; D009363:Neoplasm Proteins; D011518:Proto-Oncogene Proteins; D018121:Receptors, Cytokine; D053628:Receptors, Thrombopoietin; D014157:Transcription Factors; C082218:MPL protein, human