Supplemental Material

This article contains the following supporting material:

• Supplemental Figure - Test of nuclear pore permeability in anti-Nup153 injected cells by concomitant injection of fluorescent dextran molecules of different sizes. FITC-coupled dextran molecules, 4 kDa (A) or 40 kDa (B) in molecular mass, were injected into salivary gland nuclei with (+Ab) or without anti-Nup153 (-:Ab). To verify the effect on ribosomal RNA transport in antibody-injected cells, a Cy3-coupled oligonucleotide complementary to 18S rRNA was co-injected with dextran. The specimens were processed for in situ hybridization as described in Experimental Procedures. At two minutes after injection, both the 4 kDa and the 40 kDa dextran molecules were confined to the nucleus (upper left in A and B). After 90 minutes incubation of the glands in hemolymph, the 4 kDa dextran molecules were equally distributed in nucleoplasm and cytoplasm, whether or not the antibody was co-injected (A). On the other hand, the 40 kDa dextran remained in the nucleus both in the presence and absence of the antibody, ruling out unspecific damage to the nuclear envelope upon injection (B). As expected, the anti-Nup153 caused block in ribosomal RNA export as shown by accumulation of 18S RNA in the nucleoplasm 90 min after injection of the antibody (arrows in A and B) (cf. Fig. 5) We conclude that when the nucleocytoplasmic translocation of ribosome-sized RNP particles was blocked, passage of low molecular weight macromolecules could still take place through the nuclear pores. Scale bar, 20 μm.