Role of 4E-BP1 phosphorylation in sT-induced transformation.
(A) Rat-1 cells were stably transduced with empty vector, wild-type 4E-BP1, or constitutively active 4E-BP1AA. Empty vector or MCV sT was then cotransduced into the cells without selection, and they were grown in soft agar for 3 weeks. Colonies were stained with crystal violet, and the colony number per high-power field was determined. (B) Phase-contrast images of sT-induced Rat-1 cell colonies in soft agar. Original magnification, ×40.