Figure 2

Fluorescent-activated cell sorting (FACS) of GFP-expressing cells and GFP-negative cells from cultured A.9 populations. The figure shows the percentage of GFP-expressing cells in cultured A.9 populations at culture day 21(B) and day 23(C). Non-transfected mES cell population (ES-WT) serve as a negative control to determine the intrinsic fluorescent intensity of the cultured mES cell populations and to define positive area R2 (A). GFP-expressing cells from R2 regions and GFP-negative cells from R1 regions of cultured A.9 populations (B-C) were sorted using a Becton Dickinson FACstar flow cytometer and CellQuest^® software. Data are presented as means ± SEM. (D) show the morphology of sorted GFP-expressing cells [A.9.2+ = GFP-expressing cells purified from cultured A.9 population at culture day 21, A.9.2- = GFP-negative cells purified from cultured A.9 population at culture day 21, A.9.3+ = GFP-expressing cells purified from cultured A.9 population at culture day 23, A.9.3- = GFP-negative cells purified from cultured A.9 population at culture day 23, R1 = GFP-negative cells, R2 = GFP-expressing cells].