Figure 4.

Nuclear import occurs in the presence of antibodies to Nup153. (A) The oocyte injection protocol is shown. Antibodies were injected into the nucleus, and after a 60 min incubation, radioactively labeled import substrates were injected into the cytoplasm. After 4 h of incubation, oocytes were manually dissected, and nuclear and cytoplasmic protein was prepared and analyzed by gel electrophoresis. (B) After cytoplasmic injection, pyruvate kinase (PK) remains primarily cytoplasmic (lanes 1 and 2). In contrast, a substantial amount of an NLS-containing form of PK migrates to the nucleus after cytoplasmic injection (lanes 3 and 4). This NLS-directed import continues in the presence of anti-Nup153 antibodies (lanes 5 and 6). (C) M9-directed import of hnRNPA1 also took place in the presence of antibodies to Nup153 (lanes 3 and 4 vs. lanes 1 and 2). Luciferase, coinjected into the cytoplasm with hnRNPA1, remained primarily cytoplasmic, serving as a control for the specificity of nuclear accumulation.