Identification of the essential SNB components. (A and B) Five SNB components were reciprocally knocked down by RNAi. The efficient and specific knockdown of each protein by RNAi was detected by Western blotting (A). The molecular mass marker (kD) is shown on the left. Each protein was detected by immunofluorescence (B). (C) Quantitation of nuclear foci–positive cells in the experiments shown in B (>100 cells, ±SD, n = 3). Bar, 10 µm.