Fig. 5.
Self-sorting of ExEn cells in chimeric EBs. (A) Morphology of ExEn cells visualized by phase contrast microscopy. (Magnification: 100×.) (B and C) Immunoblotting of proteins (B) and PCR analysis of transcripts (C) in WT ES or ExEn cell lines. (D) WT ExEn cells expressing p19Arf, Gata4, and Dab2 were transduced with a vector expressing GFP, mixed with an equal number of Arf-null ES cells, and suspended in the absence of LIF to form chimeric EBs. Two days after suspension, EBs were harvested, cryosectioned, and stained with antibodies to the indicated proteins. Marked ExEn cells spontaneously sorted to the periphery of the chimeric EBs and completely segregated from DAPI-stained ES cells in the inner mass. (Scale bars, 100 µm.)