title: Identification of functional domains of the human thrombopoietin receptor required for growth and differentiation of megakaryocytic cells.
abstract: To identify the functional domains of the human thrombopoietin (TPO) receptor essential for proliferation and megakaryocytic differentiation, we introduced human wild type c-mpl cDNA and deletion mutants of c-mpl cDNA into the human erythropoietin (EPO)-dependent cell line UT-7/EPO that does not express endogenous c-Mpl. TPO induced the proliferation and megakaryocytic differentiation of UT-7/EPO expressing wild type c-Mpl, as evidenced by increased levels of the CD41 antigen specific for cells of the megakaryocytic lineage and by changes in morphology. Mutational analysis of the cytoplasmic domain of c-Mpl identified four functional regions: (a) two C-terminal regions (amino acids 575-586 and 615-630) containing a domain essential for cell proliferation and megakaryocytic differentiation but not for DNA synthesis; (b) a region (amino acids 587-614) containing a negative domain for TPO-induced cell proliferation and megakaryocytic differentiation; and (c) a region (amino acids 565-574) including a box2 motif that is required for DNA synthesis. These deletion mutants will provide useful materials for analyzing the signals specific for TPO-induced proliferation and megakaryocytic differentiation.
authors.affiliation: Division of Hematology, Department of Medicine, Jichi Medical School, Tochigi-ken 329-04, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Takatoku
authors.forename: M
authors.initials: M
authors.lastname: Kametaka
authors.forename: R
authors.initials: R
authors.lastname: Shimizu
authors.forename: Y
authors.initials: Y
authors.lastname: Miura
authors.forename: N
authors.initials: N
authors.lastname: Komatsu
mesh_terms: D002454:Cell Differentiation; D002455:Cell Division; D002478:Cells, Cultured; D018076:DNA, Complementary / Q000032:analysis / Q000235:genetics; D017353:Gene Deletion; D006801:Humans; D008533:Megakaryocytes / Q000166:cytology* / Q000378:metabolism; D009363:Neoplasm Proteins; D011518:Proto-Oncogene Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D018121:Receptors, Cytokine; D053628:Receptors, Thrombopoietin; D017421:Sequence Analysis; D015398:Signal Transduction
chemical_list: D018076:DNA, Complementary; D009363:Neoplasm Proteins; D011518:Proto-Oncogene Proteins; D018121:Receptors, Cytokine; D053628:Receptors, Thrombopoietin; C082218:MPL protein, human