Fig. 3. The inhibitory effect of EDN3 on lineage commitment and differentiation of EPCs is reversible. Colonies from embryonic EPCs (A,B,D,E) were maintained in standard medium (CM; A,D) or standard medium supplemented with 10 nM EDN3 (CM+EDN3; B,E) and immunostained for MITF (A,B) or SMA (D,E). (C,F) Images of cultured SkMe15 cells known to express MITF [American Type Culture Collection, ATCC (Du et al., 2003)] (C) and a cell in a primary embryonic gut culture that expresses SMA (F). (G) The culture conditions of freshly isolated (day 0) EPCs. At the end of the culture period (day 12) colonies in each condition were fixed and immunostained for TuJ1 (H,J,L,N) or GFAP (I,K,M,O). All colonies were counterstained with DAPI.