The model system of embryonic stem (ES) cell differentiation in vitro via cellular aggregates (embryoid bodies, EBs) can be used to analyze cell differentiation from a pluripotent stem cell via progenitor cells up to terminally differentiated cell types. ES cells are known to be pluripotent; they have the capacity to differentiate into any cell lineage of the three germ layers. Using various ES cell lines, we characterized chondrogenic and osteogenic differentiation in EBs by histochemical staining, immunostaining, mRNA-in situhybridization, and reverse transcriptase polymerase chain reaction analysis. Here, we describe in detail our established protocols to analyze chondrogenic differentiation of ES cells. We summarize different ways to modulate ES cell-derived chondrogenic differentiation.
