FIG. 4.

Inactivation of both p53 and the Rb family are required for Ras-dependent, anchorage-independent proliferation. Pools of drug selected Schwann cells (4 × 10³) expressing dnp53 with wild type (WT) or mutants of the N terminus of LT (N-LT), together with Ras or the empty vector LXSN, were seeded in agarose. After 2 weeks the colonies were stained with neutral red prior to being counted and photographed. Assays were carried out in duplicate, and a representative result of three independent assays is shown.