Expression of p21, p27 and p57 in TSCs and TGCs.

Cells were stained for the indicated protein, or for DNA, or for incorporation of EdU (S-phase cells) as described in Figures 1–4. M-phase cells were identified by the presence either of condensed chromatids or of mitotic figures. TGCs were examined three (3) days after FGF4 deprivation of TSCs. A minimum of 100 cells was scored in each case in order to determine the fraction of cells undergoing the indicated event. %G phase cells = 100– (%S phase cells+%M phase cells).