Inhibitory effects of FOG-1 expression on mature mast cells. (A) Giemsa staining of mast cells. Day 21 indicates mast cells differentiated without expression of FOG-1. Day 28 and Day 35 indicate mast cells in which FOG-1 was expressed between days 21 and 28, respectively. Bar represents 50 μm. (B) Total numbers of cells. The duration of FOG-1 expression is shown in the left panel. (C) The percentage of dead cells at day 35. The duration of FOG-1 expression is as shown in panel B. Error bars represent SEM. (D,E) RT-PCR analysis of transcription factors and mast cell–specific genes.