Fig. 3. Morphological differences among Evi1-expressing clones and control P19 cells cultured as monolayers in the absence of RA. Represented are micrographs of wild-type P19 cells (a), vector-transformant P19 clone (Mock; c), and Evi1-transformant clone (D2; d); under monolayer culture without RA. Wild-type P19 cells were cultured with RA and aggregation for 2 days and additional 2 days replating without RA (day 4; b).