title: Cellular and molecular characterization of the role of the flk-2/flt-3 receptor tyrosine kinase in hematopoietic stem cells.
abstract: The flk-2/flt-3 receptor tyrosine kinase was cloned from a hematopoietic stem cell population and is considered to play a potential role in the developmental fate of the stem cell. Using antibodies derived against the extracellular domain of the receptor, we show that stem cells from both murine fetal liver and bone marrow can express flk-2/flt-3. However, in both these tissues, there are stem cell populations that do not express the receptor. Cell cycle analysis shows that stem cells that do not express the receptor have a greater percentage of the population in G0 when compared with the flk-2/flt-3-positive population. Development of agonist antibodies to the receptor shows a proliferative role for the receptor in stem cell populations. Stimulation with an agonist antibody gives rise to an expansion of both myeloid and lymphoid cells and this effect is enhanced by the addition of kit ligand. These studies serve to further illustrate the importance of the flk-2/flt-3 receptor in the regulation of the hematopoietic stem cell.
authors.affiliation: Department of Molecular Biology, Cell Genetics, Genetech, Inc, South San Francisco, CA.
authors.forename: F C
authors.initials: FC
authors.lastname: Zeigler
authors.forename: B D
authors.initials: BD
authors.lastname: Bennett
authors.forename: C T
authors.initials: CT
authors.lastname: Jordan
authors.forename: S D
authors.initials: SD
authors.lastname: Spencer
authors.forename: S
authors.initials: S
authors.lastname: Baumhueter
authors.forename: K J
authors.initials: KJ
authors.lastname: Carroll
authors.forename: J
authors.initials: J
authors.lastname: Hooley
authors.forename: K
authors.initials: K
authors.lastname: Bauer
authors.forename: W
authors.initials: W
authors.lastname: Matthews
mesh_terms: D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D001854:Bone Marrow Cells; D002453:Cell Cycle; D002455:Cell Division / Q000187:drug effects; D015870:Gene Expression; D006098:Granulocytes / Q000166:cytology; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000378:metabolism*; D008099:Liver / Q000166:cytology / Q000201:enzymology; D008214:Lymphocytes / Q000166:cytology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D051941:fms-Like Tyrosine Kinase 3
chemical_list: D000906:Antibodies; D000911:Antibodies, Monoclonal; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; C497971:Flt3 protein, mouse; D020794:Receptor Protein-Tyrosine Kinases; D051941:fms-Like Tyrosine Kinase 3