title: Fgd5 identifies hematopoietic stem cells in the murine bone marrow.
abstract: Hematopoietic stem cells (HSCs) are the best-characterized tissue-specific stem cells, yet experimental study of HSCs remains challenging, as they are exceedingly rare and methods to purify them are cumbersome. Moreover, genetic tools for specifically investigating HSC biology are lacking. To address this we sought to identify genes uniquely expressed in HSCs within the hematopoietic system and to develop a reporter strain that specifically labels them. Using microarray profiling we identified several genes with HSC-restricted expression. Generation of mice with targeted reporter knock-in/knock-out alleles of one such gene, Fgd5, revealed that though Fgd5 was required for embryonic development, it was not required for definitive hematopoiesis or HSC function. Fgd5 reporter expression near exclusively labeled cells that expressed markers consistent with HSCs. Bone marrow cells isolated based solely on Fgd5 reporter signal showed potent HSC activity that was comparable to stringently purified HSCs. The labeled fraction of the Fgd5 reporter mice contained all HSC activity, and HSC-specific labeling was retained after transplantation. Derivation of next generation mice bearing an Fgd5-CreERT2 allele allowed tamoxifen-inducible deletion of a conditional allele specifically in HSCs. In summary, reporter expression from the Fgd5 locus permits identification and purification of HSCs based on single-color fluorescence.
authors: Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138 Program in Cellular and Molecular Medicine, Division of Hematology/Oncology and Division of Transfusion Medicine, Department of Laboratory Medicine, Boston Children's Hospital, MA 02116.
authors: Roi
authors: R
authors: Gazit
authors: Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138 Program in Cellular and Molecular Medicine, Division of Hematology/Oncology and Division of Transfusion Medicine, Department of Laboratory Medicine, Boston Children's Hospital, MA 02116.
authors: Pankaj K
authors: PK
authors: Mandal
authors: Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138 Program in Cellular and Molecular Medicine, Division of Hematology/Oncology and Division of Transfusion Medicine, Department of Laboratory Medicine, Boston Children's Hospital, MA 02116.
authors: Wataru
authors: W
authors: Ebina
authors: Department of Pediatrics, Department of Neurobiology, Harvard Medical School, Boston MA 02115.
authors: Ayal
authors: A
authors: Ben-Zvi
authors: Program in Cellular and Molecular Medicine, Division of Hematology/Oncology and Division of Transfusion Medicine, Department of Laboratory Medicine, Boston Children's Hospital, MA 02116.
authors: César
authors: C
authors: Nombela-Arrieta
authors: Program in Cellular and Molecular Medicine, Division of Hematology/Oncology and Division of Transfusion Medicine, Department of Laboratory Medicine, Boston Children's Hospital, MA 02116 Program in Cellular and Molecular Medicine, Division of Hematology/Oncology and Division of Transfusion Medicine, Department of Laboratory Medicine, Boston Children's Hospital, MA 02116 Harvard Stem Cell Institute, Cambridge, MA 02138.
authors: Leslie E
authors: LE
authors: Silberstein
authors: Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138 Program in Cellular and Molecular Medicine, Division of Hematology/Oncology and Division of Transfusion Medicine, Department of Laboratory Medicine, Boston Children's Hospital, MA 02116 Department of Pediatrics, Department of Neurobiology, Harvard Medical School, Boston MA 02115 Harvard Stem Cell Institute, Cambridge, MA 02138 derrick.rossi@childrens.harvard.edu.
authors: Derrick J
authors: DJ
authors: Rossi
mesh_terms: D000483:Alleles; D064591:Allografts; D000818:Animals; D000943:Antigens, Differentiation / Q000096:biosynthesis / Q000235:genetics; D001853:Bone Marrow / Q000378:metabolism*; D016026:Bone Marrow Transplantation; D005434:Flow Cytometry / Q000379:methods; D005786:Gene Expression Regulation / Q000502:physiology*; D017930:Genes, Reporter / Q000502:physiology; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism*; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic
chemical_list: D000943:Antigens, Differentiation; C574715:FGD5 protein, mouse; D020662:Guanine Nucleotide Exchange Factors