In Vivo Clonal Analysis of Aged Hematopoietic Stem Cells: Single-Cell Transplantation.

Hematopoietic stem cells (HSCs) display heterogeneity in their characteristic features of undergoing self-renewal and multipotency within the blood system. While the same cell surface protein markers can be used to isolate HSCs from young and aged mice, recent studies have shown that their functional potential changes throughout the aging process. However, many of these conclusions have been the result of conventional HSC transplantation assays. These methods, though valuable, undermine not only the effective analysis of the underlying heterogeneity in aged HSC function, but also a full understanding of aged HSC differentiation potential to all five blood lineages. In this chapter, we describe a method to perform in vivo clonal analysis of aged HSCs using single-cell transplantation, incorporating a five-blood lineage tracing system using the Kusabira-Orange (KuO) trancsgenic mouse line.