title: Enforced expression of PU.1 rescues osteoclastogenesis from embryonic stem cells lacking Tal-1.
abstract: Transcription factor T-cell acute lymphocytic leukemia 1 (Tal-1) is essential for the specification of hematopoietic development. Mice lacking Tal1 fail to generate any hematopoietic precursors. Using our co-culture system with stromal cells, we demonstrate that enforced expression of the transcription factor PU.1 under tetracycline control in Tal1-null embryonic stem (ES) cells rescues the development of osteoclasts and macrophage-like phagocytes. It was low efficiency compared with wild-type ES cells; other hematopoietic lineage cells of granulocytes, B cells, mast cells, megakaryocytes, and erythroid cells were not generated. Osteoclasts developed in this culture were multinucleated and competent for bone resorption. Their development depended on macrophage colony-stimulating factor and receptor activator of nuclear factor kappaB ligand. The majority of cells with the potential to differentiate into osteoclasts expressed fetal liver kinase 1 (Flk-1) and could be isolated using anti-Flk-1 antibody. These results suggest that the expression of PU.1 is a critical event for osteoclastogenesis and that Tal-1 may lie upstream of PU.1 in a regulatory hierarchy during osteoclastogenesis.
authors.affiliation: Division of Immunology, Department of Molecular and Cellular Biology, School of Life Science, Faculty of Medicine, Tottori University, 86 Nishi-Machi, Yonago, Tottori, 683-8503, Japan. tsune13@grape.med.tottori-u.ac.jp
authors.forename: Motokazu
authors.initials: M
authors.lastname: Tsuneto
authors.forename: Akira
authors.initials: A
authors.lastname: Tominaga
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Yamazaki
authors.forename: Miya
authors.initials: M
authors.lastname: Yoshino
authors.forename: Stuart H
authors.initials: SH
authors.lastname: Orkin
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Hayashi
mesh_terms: D051792:Basic Helix-Loop-Helix Proteins; D002454:Cell Differentiation / Q000502:physiology; D004268:DNA-Binding Proteins / Q000235:genetics*; D004622:Embryo, Mammalian / Q000166:cytology*; D005786:Gene Expression Regulation; D006801:Humans; D010010:Osteoclasts / Q000166:cytology / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis* / Q000235:genetics*; D013234:Stem Cells / Q000166:cytology*; D017154:Stromal Cells / Q000166:cytology / Q000378:metabolism*; D000073942:T-Cell Acute Lymphocytic Leukemia Protein 1; D015534:Trans-Activators / Q000096:biosynthesis* / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics*; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000235:genetics; D000099232:Proto-Oncogene Protein Spi-1
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D011518:Proto-Oncogene Proteins; D000073942:T-Cell Acute Lymphocytic Leukemia Protein 1; D015534:Trans-Activators; D014157:Transcription Factors; D040301:Vascular Endothelial Growth Factor Receptor-2; D000099232:Proto-Oncogene Protein Spi-1; C067143:TAL1 protein, human