Activated Notch2, Notch3, and Notch4 and the downstream target Hes1 are capable of inducing B-cell death. (A) V9 cells were transduced with the indicated retroviral supernatant, and the percentage of GFP⁺ cells was determined as described in Figure 1. (B) Transduced GFP⁺ V9 cells were purified by FACS at 20 hours after transduction. The GFP⁺ cells were cultured for 24 hours, stained for annexin V, and analyzed by FACS. The histograms of annexin V staining are shown. (C) 70Z cells were transduced with the indicated retrovirus, and NGFR⁺ cells were purified on a MACS column at 48 hours after transduction. RNA was isolated, and RT-PCR to detect Hes1 transcription was performed. HPRT RT-PCR was performed as an internal control. (D) 70Z cells were transduced with the indicated retrovirus, and GFP⁺ cells were purified by FACS 24 hours later. The GFP⁺ cells were harvested, and the percentage of subdiploid (apoptotic) cells was determined by PI staining and FACS analysis. Mean and standard deviation are shown.