Fig. 1. Formation of distinct cell arrangements during Pax3-induced aggregation of Saos-2 cells. Representative phase-contrast images depicting the arrangement of Saos-2 cells postinfection at the times indicated, infected with control Ad-ß-gal infected (A-C) or Ad-Pax3^flag (D-E) adenoviruses. Beginning at 48 hours postinfection, in contrast to the random arrangement of control infected cells (A-C), many Pax3-infected cells could be found in columnar (oriented parallel to the plane of the substratum) arrangements (D). These columnar arrangements persisted in Pax3-infected cells as they formed aggregates (E-F). Bars, 80 µm.