Patent ID: 7795023

Claim:
A method for identifying if a pre-mesenchymal, pre-hematopoietic stem cell is present in a population of cells, comprising: (a) obtaining a population of cells from the bone marrow of an animal; (b) culturing in a collagen gel the cells of (a) in medium comprising 1.0% or less serum in vitro for at least seven days with a polypeptide comprising a fusion polypeptide, wherein the fusion polypeptide comprises a collagen-binding domain and TGF-β1 or active fragment of TGF-β1; (c) culturing the TGF-β1 responsive cells of (b); and (d) detecting expression of osteoblast specific factor 2 (Osf2) in said TGF-β1 responsive cells; thereby identifying a cell that expresses Osf2 as a pre-mesenchymal, pre-hematopoietic stem cell.