Lef1 is required for survival of T-cell lymphomas. (A) Northern blot of mRNA extracted from 0531 and 1.F9 cells infected with Banshee (“B”) or LEF1 siRNA (siRNA) virus 48 hours after infection. The blot was probed sequentially with cDNA probes complementary to Lef1, c-myc, and actin. (B) Lymphoma lines were infected with Banshee control (“B”; closed symbols) or Lef1 siRNA (si; open symbols) retrovirus, and the percentage of cells expressing GFP was determined every 24 hours by flow cytometry. The relative percentage of GFP⁺ compared with 24 hours is shown. (C) Flow cytometric cell-cycle analysis of 0531 cells infected with Banshee (left) or Lef1 siRNA virus (right) after a 30-minute pulse with BrdU and staining with anti-BrdU and propidium iodide. The percentage of cells in each gate is indicated. (D) Forward light scatter for GFP⁺ (■) and GFP⁻ (▩) cells from Banshee- or Lef1 siRNA-infected lymphomas 48 hours after infection.