Preparation of defined human embryonic stem cell populations for transcriptional profiling.

This unit describes a useful approach to preparing highly reproducible samples of human embryonic stem cell (hESC) total RNA suitable for transcriptional profiling from heterogeneous mixtures of cells containing undifferentiated hESC and differentiated cell types. In this unit, fluorescence-activated cell sorting (FACS) is used to sub-fractionate hESC populations on the basis of their levels of co-expression of two previously published hESC surface markers, CD9(TG30) and GCTM-2. This sub-fractionation allows for the separation of undifferentiated hESC (CD9hi, GCTM-2hi) from the early stages in hESC differentiation (CD9neg or low, GCTM-2neg or low).