Reduction of SMN expression with RNAi disrupts CBs as well as gems. A) HeLa cells microinjected with siRNA duplexes to reduce SMN expression (demonstrated by red signal in TR-dextran panel, far right, and arrows) lack SMN-containing gems (left hand panel, green on overlays). Antibody detection of coilin (top row, magenta on overlays; bottom row, green on overlays) shows reduced CBs and increased diffuse nucleoplasmic signal. Antibody detection of the non-snRNP splicing factor, SC-35 (bottom row, magenta on overlays), reveals intact nuclear speckles. Bar = 10 μm. B) Undifferentiated (top row) and BDNF-differentiated (bottom row) SH-SY5Y cells microinjected with siRNA duplexes (red signal in TR-dextran panel, far right, and arrows) lack SMN-containing gems. Coilin-containing CBs (magenta on overlays) are also absent. Bar = 10 μm.