Abstract: Populations enriched for myogenic progenitors are obtained by selection on the basis of expression of specific cell surface markers. The muscle progenitor cells are characterized as being CD45? and CD34+, and may further be characterized as lacking expression of Mac-1 (CD11b) and positive for expression of CXCR4 (CD184) and ?1-integrin (CD29).

Abstract: A substantially enriched mammalian hematopoietic cell subpopulation is provided, which is characterized by progenitor cell activity for lymphoid lineages, but lacking the potential to differentiate into myeloid and erythroid lineages. Methods are provided for the isolation and culture of this common lymphoid progenitor cell (CLP). The cell enrichment methods employ reagents that specifically recognize CDw127 (IL-7 receptor ?); CD117 (c-kit) protein, in conjunction with other markers expressed on lineage committed cells. The murine cells are also characterized as expressing low levels of sca-1 (Ly-6E and Ly-6A). The CLPs are predominantly cycling, blast cells. These cells give rise to B cells, T cells and natural killer cells, as evidenced by their growth and differentiation in vitro and in vivo.

Abstract: A substantially enriched mammalian hematopoietic cell population is provided, which is characterized as a progenitor cell committed to the megakaryocyte lineage. Methods are provided for the isolation and culture of these cells. The cell enrichment methods employ reagents that specifically recognize CD9 and CD41, in conjunction with other markers expressed on lineage committed progenitor cells. These cells give rise exclusively to megakaryocytes and platelets, as evidenced by their growth and differentiation in vitro and in vivo.

Abstract: Reagents that block the extracellular activation of &bgr;-catenin are used to induce quiescence in normal stem cells, in order to reduce the killing of stem cells by anti-proliferative agents.

Abstract: Methods and compositions are provided for the identification of stem cells and cancer stem cells. &bgr;-catenin is also identified as a target for the development of therapeutic moieties against hematopoietic tumors, i.e. leukemia and lymphoma cells, which may include screening assays directed at &bgr;-catenin, or members of the &bgr;-catenin signaling pathway. Cellular proliferation in hematopoietic cells can be altered by introducing stabilized &bgr;-catenin into a hematopoietic cell that is altered in its ability to undergo apoptosis but which is not fully transformed. The immortalized cells are useful in screening assays, and in the analysis of pathways by which hematopoietic cells undergo transformation.

Abstract: Enriched neural stem and progenitor cell populations, and methods for identifying, isolating and enriching for neural stem cells using reagent that bind to cell surface markers, are provided.

Abstract: Enriched neural stem and progenitor cell populations, and methods for identifying, isolating and enriching for neural stem cells using reagent that bind to cell surface markers, are provided.

Abstract: Enriched neural stem and progenitor cell populations, and methods for identifying, isolating and enriching for neural stem cells using reagent that bind to cell surface markers, are provided.

Abstract: Enriched neural stem and progenitor cell populations, and methods for identifying, isolating and enriching for neural stem cells using reagent that bind to cell surface markers, are provided.

Abstract: The present invention provides a method for optimizing gene transfer into hematopoietic stem cells (HSCs) by contacting the cells with hydroxyurea prior to gene transfer to induce HSCs in G0 into active cell cycle. This method is useful for treating patients suffering from a disease that is suitably treated by gene therapy or involves hematopoietic cells. A method is also provided for enhancing the efficacy of bone marrow transplantation by administering hydroxyurea to increase HSC yields.

Abstract: Human hematopoietic stem cells are provided by separation of the stem cells from dedicated cells. The stem cells may than be maintained by regeneration in an appropriate growth medium. Means are provided for assaying for the stem cells as to their capability for producing members of each of the hematopoietic lineages. A method for treating a human by implanting a cellular composition comprising greater than 90% human hematopoietic stem cells is also disclosed.

Abstract: A subpopulation in the CD4.sup.+ 8.sup.+ (DP) thymic blast population is identified that is the precursor for thymic T cells. All such progenitors are c-kit.sup.+. The c-kit.sup.+ subset expresses lower levels of CD4 and CD8 than the large and small DP c-kit- cells. These DP.sup.int c-kit.sup.+ cells differentiate to thymic T cells rapidly on heterogenous thymic stromal cell cultures. Similar maturation takes place in vivo over 4 days. A method for isolating the cells which are c-kit.sup.+ and which express intermediate or low levels of CD4+/CD8+ is also disclosed.

Abstract: Human hematopoietic stem cells are provided by separation of the stem cells from dedicated cells. The stem cells may than be maintained by regeneration in an appropriate growth medium. Means are provided for assaying for the stem cells as to their capability for producing members of each of the hematopoietic lineages.

Abstract: Human hematopoietic stem cells are provided by separation of the stem cells from dedicated cells. The stem cells may than be maintained by regeneration in an appropriate growth medium. Means are provided for assaying for the stem cells as to their capability for producing members of each of the hematopoietic lineages.

Abstract: Human hematopoietic stem cells are provided by separation of the stem cells from dedicated cells. The stem cells may than be maintained by regeneration in an appropriate growth medium. Means are provided for assaying for the stem cells as to their capability for producing members of each of the hematopoietic lineages.

Abstract: Human hematopoietic stem cells are identified according to expression of specific cell surface markers. Substantially homogenous stem cell compositions are obtained by selective isolation of cells free of markers associated with differentiated cells, while displaying epitopic characteristics associated with the stem cells. The stem cells may then be maintained by regeneration in an appropriate growth medium. Means are provided for assaying for the stem cells as to their capability for producing members of each of the hematopoietic lineages.

Abstract: Methods and compositions for modifying the lifespan of progeny cells of mammalian hematopoietic stem cells, particularly myeloid series cells, are provided. Transgenic nonhuman mammals also are provided which produce transgenic myeloid cells having an altered lifespan.

Abstract: Human hematopoietic stem cells are provided by separation of the stem cells from dedicated cells. The stem cells may than be maintained by regeneration in an appropriate growth medium. Means are provided for assaying for the stem cells as to their capability for producing members of each of the hematopoietic lineages.