Isolation and Characterization of Mouse Side Population Cells

The side population (SP) is a subpopulation of mouse bone marrow cells highly enriched for hematopoietic stem cell activity. The SP is identified using flow cytometry as a minor population that efficiently effluxes the DNA-binding dye Hoechst 33342 relative to the rest of the bone marrow. Phenotypic and functionally analysis has established SP cells as highly phenotypically homogeneous and functional active. In this chapter we describe a detailed protocol for the purification of murine bone marrow SP cells based on Hoechst dye efflux in combination with the presence of HSC surface markers.