Fig. 4. (i) Maximum intensity projections of deconvolved serial sections through a cell from line HeLa (D). Immunodetection with antibodies to p80-coilin (A) and SMN (B) demonstrate that, in addition to large Cajal bodies containing both p80-coilin and SMN (arrows in A and B), these cells also contain smaller nuclear bodies containing p80-coilin in the absence of SMN (arrowhead in A) and containing SMN in the absence of p80-coilin (arrowhead in B). Bar, 10 µm. (ii) Single confocal sections of a cell from line HeLa (D) transfected with an expression plasmid encoding YFPSmB and fixed after 16 hours (A-D). The prominent Cajal body containing newly imported snRNP (arrow in B) also contains endogenous p80-coilin (arrow in A) and SMN (arrow in C). Additional bodies containing p80-coilin, but not new snRNP nor SMN, are also seen (arrowheads in A,D, see also inset magnified view in A-D). Bar, 10 µm. Maximum intensity projections of deconvolved serial sections through heterokaryons of cells from line HeLa (D) fused to a cell from line YFPSmBE1 fixed 1 hour after fusion (E-H). YFPSmB has accumulated in Cajal bodies of nuclei from line HeLa (D) (arrows in F). These bodies also contain endogenous p80-coilin (arrow in E) and SMN (arrow in G). Numerous additional bodies containing p80-coilin but neither new snRNP nor SMN are also seen (arrowheads in E,H). Bar, 10 µm.
